(This article was originally published in Freshwater and Marine Aquarium Magazine, Nov 1985; pp. 52-63. It is here reproduced with the permission of author Dr. Wayne S. Leibel.).
(Editor Note by Juan Miguel Artigas Azas: The present article as originally appeared, included some genera names no longer in use due to taxonomy evolution. In an attempt to avoid confusion and take advantage of the possibility of updating electronic publications in the WWW, I have updated in this article the genera name of Cichlasomines now Heroines genera mentioned in this paper to reflect their current status, jul-97).
|Figure 1: Mature female Basketmouth Cichlid, Acaronia nassa (5.5 inch TL). Photo by Wayne S. Leibel.|
There are a number of aquarium fishes which are strangers to the average aquarist. Many because of their rarity in nature, others because of unmanageable size or behavior, or unreasonable maintenance requirements. Still another group of "phantom" fishes owe their missing status in the hobby to the absence of accurate and flattering photos, or to unfavorable reviews by noted authorities that appear in the available hobby compendia. Such is the misfortune of Acaronia nassa, the Basketmouth, a beautiful and highly interesting Neotropical cichlid which, although plentiful in nature, has been ignored by aquarists for years. The reason for this is all too clear: couple the truly forgettable Schultz photo of two washed-out frightened juveniles with the accompanying verbal hatchet job (Axelrod 1962, F-11.00) and you have a fish that no one wants to keep. Acaronia nassa (Heckel 1840) can be aggressive and they do have special requirements, but no more so than many of the huge Mesoamerican Guapotes being kept and spawned by Heroine freaks. And, as the above photograph demonstrates, well-maintained, sexually mature individuals are unquestionably beautiful. This article, then, is an attempt to right an unfair wrong that has befallen this highly desirable Neotropical cichlid. For many of you, it may well be your first acquaintance with the Basketmouth. As the following paragraphs should make amply clear, it should not be your last.
Acaronia nassa was first described by Heckel in 1840 as Acara nassa from material collected by Natterer from the Amazon. The specific nomen nassa, which translates (from latin) as "a wicker fish trap" (New College Latin & English Dictionary) is an adequate description of how this fish makes its living. Heckel so named this fish on the strength of Natterer's report that the natives call it Bocca de Juquia, meaning "Fish Trap Mouth." Heckel's (1840) description of the fish is inordinately complete and, his sense of beauty apparently tweaked, it ends (uncharacteristically for a scientific description) with a short discourse on the fish's life colors. Heckel notes, with obvious aesthetic pleasure, the bright Mother-of-Pearl trimming and red-gold cast of the body. If Heckel had been in the ornamental fish business, I'm sure he'd have wired Natterer to send several boxes of them!
Although sufficiently astute to sort several of the more distinctive specimens in Natterer's collection into separate new genera (e.g., Uaru, Symphysodon, Pterophyllum, Crenicichla, and Heros, for example) Heckel (1840) described no fewer than twenty-one species in his new genus Acara. These included many which are still retained in the genus Aequidens (Eigenmann and Bray 1894; the Acaras of the aquarium hobby) and also a fair number of obviously unrelated forms including the Oscar (now Astronotus), several Geophagines (Geophagus brasiliensis and surinamensis), and the African Mouthbrooder, Haplochromis desfontainesi (??)!!
Although Günther (1862) apparently accepted Heckel's (1840) placement of nassa in the mixed-bag genus Acara, he did suggest that Heckel's new species Acara cognatus and A. unicolor, were in fact identical with Acaronia nassa. Steindachner (1875) formally synonymized these latter two with nassa and erected a monotypic subgenus Acaropsis (opsis = appearance, e.g., looks-like) for Heckel's nassa which he felt (correctly) differed substantially from the other species in the genus Acara. Eigenmann and Bray (1894) later promoted Acaropsis to full generic rank and distinguished it from their new genus Aequidens, where all but the obvious misfits from Acara Heckel were moved (see Loiselle 1983 for an account of the Acara-Aequidens situation), on the basis of anatomical features responsible for its basket-like mouth. Like Aequidens species, Acaropsis nassa had three spiny anal fin rays and typical "Acara" gill morphology: no lobe on the first gill arch and few, short rakers along the free edge. Unlike typical Aequidens species, Acaropsis nassa had a much larger mouth, highly-protractile premaxillaries, and exposed maxillaries all related to its occupation as an efficient gape-and-suck predator (Figure 2; see Eaton 1943). As Pellegrin (1903) noted, Acaropsis nassa is (related) to Aequidens as the snook Petenia splendida (Figure 3) is to Cichlasoma: both have highly-developed jaw mechanisms. Cichocki (1976) more recently has suggested on the basis of arguable cladistic analysis that Acaronia nassa is more closely-related to Chaetobranchus.) It is no accident that members of the genus Caquetaia (e.g., spectabile, krausii, myersii) which are closely related to the snook are known collectively as false Basketmouths in the hobby (Figure 4).
Myers (1940) pointed out that the name Acaropsis suggested by Steindachner (1875) was, in fact, preoccupied by a genus of spiders that had been so named several years before Steindachner chose it for nassa (Moquin-Tandon, 1863). By the law of historical precedence, Acaropsis was the property of this arachnid genus, unavailable to Steindachner, and thus retroactively invalid. Myers (1940) suggested in instead Acaronia which was available and currently serves as the generic nomen.
It is not clear how many species should be recognized in the genus Acaronia Myers 1940. The previously mentioned synonymization of Heckel's A. unicolor and A. cognatus with nassa has been accepted by all students of Neotropical Cichlidae since Steindachner's (1875) decision to lump them. However, Miranda-Ribeiro (1918) described a second species, Acaropsis (Acaronia) rondoni from the Rio do Sangue in the Matto Grasso region of Brazil. Although I do not have access to the original description, Fowler (1954) offers a line drawing of the fish based on a photograph from the Miranda-Ribeiro paper. Unfortunately, no meristic or morphometric data accompany the figure, and the overall body shape and mouth configuration as depicted by Fowler (1954) in comparison to a companion figure of Acaronia nassa, also drawn from a Miranda-Ribeiro photograph, look sufficiently different to my untrained eye to leave me skeptical of the validity of this species' placement in the genus Acaronia. No mention of Miranda-Ribeiro's (1918) rondoni are found in any of the relevant post-1920s papers dealing with Neotropical Cichlidae which, given the obscurity of the journal in which he habitually published, is not surprising. (Similar lack of general ichthyological acceptance based solely on obscurity greeted his correct and now accepted erection of the genus Gymnogeophagus in that same 1918 paper (see Gosse (1975). However, Eigenmann and Allen (1942) who describe a third Acaronia species make no mention of Miranda-Ribeiro's (1918) rondoni while listing this paper in their bibliography (padding the bibliography?). Goldstein (1973) suggests on the (uncited) authority of Hermann Meinken that Acaropsis rondoni is actually an Apistogramma species, however Miranda-Ribeiro described both Acaropsis rondoni and Heterogramma (Apistogramma) rondoni in the same 1918 paper and they both appear as separate entries in Fowler (1954). (Kullander (1980) suggests that Heterogramma rondoni may be related to, if not identical with, Apistogramma borelli.) Acaronia rondoni (Miranda-Ribeiro 1918) may well be valid, but given its type location, an area not frequently collected and certainly not a locus for commercial exportation, it is doubtful that this fish ever has been, or ever will be, in the aquarium hobby.
Allen (in Eigenmann and Allen, 1942) described a third Acaronia species; trimaculata, from material collected by Morris from Iquitos Peru in 1922. Although Allen is clearly familiar with Acaronia nassa having described a specimen from the Amazon in the entry immediately preceding his description of trimaculata and having noted therein the key distinguishing character of highly protractile premaxillaries, he fails to mention this diagnostic anywhere in his description of trimaculata. In fact, he notes that trimaculata is "an Acaronia of very different form from the genotype nassa..." (page 389). The rest of the verbal description suggests an Aequidens of the stout, generalized, tetramerus group (see Loiselle, 1984), an impression that is confirmed by the photograph that accompanies the description (Plate 22, figure 8). Given that Allen (1942) failed to note the serrated preoperculum of the new species hercules that he also describes in this work and incorrectly places it in the genus Aequidens (it is, in fact, a Crenicara synonymizable with C. punctulata Kullander 1978), I strongly doubt his species Acaronia trimaculata. Kullander (1984) in fact, has recently synonymized it with Aequidens uniocellatus.
Thus it appears that Acaronia Myers 1940 is a monotypic genus with the sole species nassa (Heckel 1840) distributed cosmopolitanly throughout the Amazon and north to Guyana (Steindachner 1875, etc.) and possibly occurring in the Orinoco Drainage in Venezuela (Pellegrin 1903, Eigenmann and Allen 1942) as well as the La Plata Drainage (Paraguay, Bolivia; Eigenmann and Allen 1942). (Editor note: Since the writting of this article there has been a second species described from "Small drying pool off road from El Burro to Puerto Ayacucho, Departamento Ature, Amazonas, Venezuela" by Sven Kullander in 1989, namely Acaronia vultuosa).
An interesting aside involves the description of a juvenile Acaronia nassa, morphologically somewhat different from adult fish (Figure 5), as an Apistogramma species. Fowler (1940) described Apistogramma ambloplitoides on the basis of a single 77 mm specimen collected by Morrow from Peru. His figure of the holotype which appears again in Fowler (1954) is a dead-ringer for a juvenile Acaronia nassa. Kullander (1980) has confirmed by re-examination both Fowler's (1940) data and the correct assignment of this juvenile fish to Acaronia nassa. Unfortunately, this correction was not made before the species name and an inaccurate photograph was recorded for posterity in Axelrod's (1962) Exotic Tropical Fish (entry F-66.00). The fish picture is regrettably not even close to Fowler's (1940) figure of the holotype. I find particularly humorous the comment that this fish is .".. not at all like most of the Apistogramma species, and this fish could easily be mistaken for one of the Aequidens or Cichlasoma species." Indeed. The entry does not appear in the new Expanded Edition (Axelrod 1980).
Biotope and Natural History
The little that we know regarding the natural history of the Basketmouth cichlid comes from observations by Rosemary Lowe-McConnell (1964, 1969) from Guyana. In Guyana, Acaronia nassa is widely distributed in a number of distinct biotopes. During the rainy season, typically April through September north of the Equator, the rivers rise and flood the surrounding savannah areas. The fish likewise spread out over the flooded savannah. Food is abundant and many species spawn at this time. At the end of the rains, the savannah dries quickly. Many fish run back to the main rivers, but many are stranded in open savannah pools (which shrink but remain full) until the rains free them again the following year. The savannah pools are typically clear, about 2 meters in maximum depth and several hundred meters in circumference. The bottom is muddy and quite rich in vegetation. Acaronia nassa (along with Satanoperca jurupari and Geophagus surinamensis) are quite plentiful in these pools.
Acaronia nassa is also quite common in pools adjacent to, and often connected with, the main river. These permanent pools are typically smaller than the savannah pools, edged with rock, and filled with very clear water over a mixed rock, stone and sand bottom that primarily supports a rich algal growth. Rocks and fallen tree debris provide needed hiding places for resident cichlids which include Satanoperca jurupari, Mesonauta festivum, Cichlasoma bimaculatum, and the predator Cichla occellaris. Although Acaronia nassa was occasionally taken from small creeks feeding the main river, they were never captured in the main river. (Lowe-McConnell 1964.) Acaronia nassa also is abundant in manmade trenches in coastal Guyana. On the coastal plain near Georgetown, water from the coastal rivers is diverted into a large complex of trenches (2 meters wide x 1-1.5 meters deep) that are used for irrigation and drainage of the sugar and rice fields (Lowe-McConnell 1969). The trenches are well-vegetated and contain a variety of cichlids, characins, knifefishes, and catfishes, with cichlids making up the majority (73%) of the resident fish species. Acaronia nassa along with Cichlasoma bimaculatum were the two most common cichlids in this trench system (Lowe-McConnell 1969).
Unfortunately, Lowe-McConnell (1969) offers little detail of water chemistry and conditions in these irrigation trenches (or in the pools mentioned above). However, she does record mean annual air temperatures of 83°F. (28°C) with daily fluctuations of 10°F. (5-6°C) and corresponding water temperatures from 80-96°F. (27-36°C) in the creeks and river pools of the Rupununi District, Southwestern Guyana. Gut analyses of eighty-two specimens of Acaronia nassa confirm the carnivorous lifestyle of this fish: paleomonid shrimp, dragonfly larvae, and small fish were most commonly found. Acaronia nassa are solitary, lurking predators that hang near the bottom of the trenches and capture prey by sudden protrusion of the huge mouth which creates the necessary vacuum. Although breeding was never observed, some of Lowe-McConnell's (1969) sampling data are relevant. Ripe females were caught continuously from April to November indicating a rather protracted breeding season more or less independent of rainy/dry fluctuations. When pairs were trapped together the male was generally the larger fish (average 20-30 mm longer). The mean standard length of 42 randomly caught males was 100 mm (range 10-150 mm) whereas the mean standard length for 38 caught females was 96 mm (range 70-130 mm). Gonadal inspection indicated that females matured when only 80 mm (approximately 3 inches) in standard length. No maturation size was determined for males.
As stated in the Introduction, the popularity of the Basketmouth in the American hobby suffers from the absence of good color photographs of mature specimens in any of the usual hobby compendia. The often reproduced Schultz photo of young nassa (Axelrod 1962, Goldstein 1970, 1973) and similarly, the unflattering rendering of more mature animals by Axelrod (Goldstein 1970, 1973) do the fish a grave disservice. A better image appears in Axelrod (1980, p.267) but is a dead, pinned, newly caught fish. Fig. 1 is a sexually mature female of 5 1/2" (140 mm) T.L. and is more reminiscent of the iridescent beauty of this fish.
Acaronia nassa, though closely related to the genus Aequidens, has the overall appearance and demeanor of an Acara trying to be a Heroine. While the body shape has characteristics of both genera, the fiesty aggressive behavior is definitely Heroine (Figure 6). The ground color is a charcoal grey with a subtle bronze-gold wash. The center of each ventrolateral scale and many of the dorsolateral scales is bright iridescent silver creating a series of Satanoperca jurupari like parallel iridescent stripes that run the length of the animal. Three black ocelli (ringed in silver); one on the upper peduncle, one nearly mid-lateral between upper and lower lateral lines, and one small humeral ocellus just above the upper lateral line in line with the opercular margin, complete the body markings. Two additional black ocelli just under the eye; one on the cheek and one on the operculum, are ringed in silver which extends onto the face and lower lip. The facial markings are reminiscent of the African Haplochromine Haplochromis horei, and the ocellated gill plates are used like the Firemouth, Thorichthys meeki, in aggressive display (Figure 7). The iris of the relatively big eye is bright orange turning neon red during courtship and spawning. The unpaired fins are charcoal gray and maculated with faint hyaline spots on the intramembranes. The dorsal fin is edged in white and becomes produced to sweeping points (as does the anal fin) in large specimens. The paired ventrals are well-developed and the leading rays are edged in white and produced to feathered filaments in mature specimens. During courtship (see below) the body color darkens and several indistinct Aequidens-like vertical bars are expressed along with dark interorbital, nape, and nasal stripes. Frightened or newly-netted fish express a dark horizontal band extending from the eye back through the mid-lateral ocellus to the insertion of the soft dorsal, a marking characteristic of juvenile nassa (Figure 5).
The largest recorded specimen measures 240 mm (9.5 inches) in standard length (Eigenmann and Allen 1942) although sexual maturity is apparently reached at considerably smaller size (see above, Lowe-McConnell (1969). Lowe-McConnell (1969) reports sexual size dimorphism, with females of captured pairs usually 20-30 mm smaller than their male consorts. This held true for the two sexually mature pairs I acquired and whose spawning is reported below. Whether females remain smaller than males at maximum growth is unknown. There are no obvious sexual differences in finnage or coloration. However, as was true for Acarichthys heckelii, there seem to be subtle but reliable differences in the width and profile of the head. The ascending profile of the male's head is steeper and the interorbital width (head thickness) such greater than the female's. Mature specimens may be sexed directly by visual inspection of the vents (Loiselle, 1977) or following temperature-induced papilla extrusion (Leibel 1984).
General Aquarium Maintenance and Captive Breeding
Some of the bad press given Acaronia nassa by Axelrod (1960, 980) is deserved. Wild adult basketmouths are solitary, quarrelsome cichlids which are skulking, cryptic predators. They are best housed individually, preferably in medium-sized tanks separated by egg-crate dividers if courtship and eventual spawning are desired (see below). They may be housed in a community tank situation with cichlids of similar size provided the tank is large and that sufficient caves are provided for the nassa. Of course, the huge basketmouth must be reckoned with in choosing appropriate tankmates: They will eat anything they can swallow. With enough other target fish, conspecific aggression is somewhat curtailed. Water chemistry seems unimportant and the fish are fairly tolerant of slack nitrogen waste management, although they definitely appreciate, as do most fish, frequent massive water changes. They are likewise tolerant of a wide range of temperature, but 78-84°F. (25-29°C) seems a logical choice given their experience in the wild. They are somewhat shy and retiring, preferring soft lighting and requiring a dark cave shelter; either large diameter PVC pipe or an upturned flower pot. Here they wait for unsuspecting prey to vacuum down the hatch, although some individuals become more trusting with time and will leave their caves to beg food from their owners. They do tame down and become delightfully behavioral, but there is no mistaking Basketmouths for Oscars. Gravel is optional and may impede tank maintenance given the voracity of these fish. The Basketmouth's propensity for digging is minimal and it can be trusted with rooted plants.
Figure 2: The highly protactile jaws that make the Basketmouth a particularly efficient gape and suck predator are obvious in this preserved specimen.Photo by Wayne S. Leibel.
Figure 3: The red Snook, Petenia splendida, seen here ingesting a goldfish, is another efficient gape and suck predator with a similarly developed protrusible mouth.Photo by Jerry Walrath.
Figure 4: Caquetaia spectabile, a near relative of the snook, is one of several "False Basketmouth" cichlids available in the hobby.Photo by Bruce Smith.
Figure 5: Juvenile Acaronia nassa (c. 1.5 inch TL). Fowler (1940) incorrectly described the species Apistogramma ambloplitoides on the basis of a single juvenile Basketmouth from Peru.Photo by Wayne S. Leibel.
Figure 6: The large gape and formidable dentition of this threatening adult mean trouble for any goldfish.Photo by Wayne S. Leibel.
Figure 7: Like the firemouth, Thorichthys meeki, the basketmouth flares its operculars in aggressive display. The extended branchiostegals together with the conspicuous subocular ocelli make the head of this threatening female appear much larger and menacing.Photo by Wayne S. Leibel.
The one major drawback of this fish, at least in wild mature specimens, is that they are obligate goldfish gulpers and bottomless pits. I have tried, with little success, to convert my mature fish to frozen or prepared foods. One notable exception; some individuals (not all) will adapt to large dried krill. These are taken (with a dash and a splash) from the surface only and are ignored once they sink as are other motionless foods. I would suspect that earthworms (which would sink) would be ignored, but that mealworms, which float, might alternate successfully with goldfish. The high temperature/starvation strategy which is successful with many other problem feeders is not uniformly successful with this fish. I have had much better success weaning small wild specimens (2-3 inch) away from live foods in the past. Luckily, the tank-raised fish take all prepared and frozen foods from both the surface and the bottom.
Aside from their intraspecific aggressiveness when sexually mature (juveniles are social) and their requirement for huge quantities of live food, these are industrial strength cichlids whose ability to adapt to a wide variety of water chemistries and conditions makes them possible for aquarists of all abilities to maintain successfully.
Although apparently quite common in Guyana and, presumably, in the Amazon, Acaronia nassa is only infrequently available in the hobby, usually as single, juvenile contaminants of Apistogramma steindachneri or Cichlasoma bimaculatum shipments to be cherry-picked by observant and knowledgeable cichlidophiles. They are easily identified: they are the big-eyed lurkers with trap-door mouths reminiscent of an amphibious assault vehicle. Up until my current batch, I had seen and purchased roughly one half-dozen individuals of various sizes over the past eight years. It was therefore quite a shock to encounter four, five inch (total length) specimens in Martin's Aquarium, Philadelphia on an impulsive stop there enroute to a whirlwind tour of the city with visiting friends from Boston (actually two of them were rabid aquarists and demanded that we stop). The Basketmouths, being sold as Aequidens pulcher which they did resemble in their current state of wreckage, looked as though they had been run through the bass-o-matic: open sores, clouded eyes, fins rotted to the peduncle. I knew it would take much time and effort to get them back into condition, but their scarcity and size made it worth the gamble. Compounding the problem was the very brisk October weather that had seemingly blown into town with my Bostonian friends the previous night. The fish would have to sit, boxed, in the unheated car for at least twelve hours. I don't recall much about the Liberty Bell or Independence Hall, so completely absorbed in worry was I that day. We arrived back in Easton after midnight, and I hurriedly settled my new charges after chipping off the icicles. Within 48 hours, they had developed an industrial-strength case of ich (cysts on cysts!) in addition to their original laundry list of physical ailments. I knew I was in trouble when they turned up their baskets at adult krill and all frozen and prepared foods I tempted them with and began to take out their frustration on each other. I placed them each in one-half of two egg-crate divided thirty gallon tanks with six inch lengths of four inch diameter PVC pipe for shelter. There they skulked, still refusing to eat, although the ich, cloudy eyes, and fin rot were considerably improved with heat and medication. Live goldfish were added and I sat back to watch the mechanics of gape-and-suck predation. None were taken while I watched nor anytime while the lights were on, but the next morning, all were gone. The next batch suffered the same nocturnal fate. It became clear that these were crepuscular predators who plied their trade in dim light. The relatively huge eyes of Acaronia nassa confer considerable advantage at sundown or sunup when less optically well-endowed fish stumble blindly and drowsily near the cave lairs where they habitually lurk. A quick protrusion of the tube-like jaw mechanism creates enough suction to draw in goldfish-sized prey within a 1-2 inch radius of the mouth. The few times they did attempt to catch mobile fish by chase, they proved to be quite inept: their aim was terrible and they were much too slow and clumsy. Any energy input derived from the effort was more than offset by the amount of work necessary. However, they were exceedingly efficient sedentary predators.
As the four animals hit their stride, collectively downing over one-hundred goldfish a week, it became clear that I should either get a second job or find another source of feeder fish: They were 15 cents apiece or 100 for $15.00 at the only local pet shop. Such a deal! Bimonthly excursions to Martin's (3 hour roundtrip) for several hundred at a time became a more practical (but wearying) strategy. Eventually two of the four would accept large dried krill, but ate these unenthusiastically and never accepted any other frozen or prepared foods.
The fish got fat and sassy, grew back their fins, spent more and more time out of their PVC caves and one pair began what appeared to be courtship through the egg crate divider a scant three months after their rescue from potential life as mean Blue Acaras in some neophyte's tank. It appeared as though I had two pair. The only obvious sexual dimorphism was the steeper angle and thicker interorbital width of the male's head (Figure 8), and the heavier abdomens of the ripening females. No other differences in coloration or finnage were apparent. One female's distended abdomen and obvious genital papilla signaled her ripeness and she began "dancing" for the male housed on the other side of her divider, swimming back and forth near the egg crate and rapidly snapping her mouth open and shut. After several hours of this ersatz courtship, when the male left his PVC to sit by the egg crate, the divider was removed and temperature hiked slowly to 95°F. (35°C) (Note: such apparently extreme temperatures fall within the natural experience of wild fish according to Lowe-McConnell (1964) and have proven useful in eliciting spawning activity in other reluctant species like Acarichthys heckelii (see Leibel 1984).
The actual courtship was unlike anything I've ever witnessed in Neotropical cichlids. The female continued her erratic, darting dance: lunging forward and sculling backward incessantly. The male would respond with opercular flaring which, given the characteristic ocelli just under the eye on the operculum, was reminiscent of similar aggressive behavior in the Firemouth, Thorichthys meeki. He would then assume a head down attitude, snapping his head from side to side (Aequidens-like), circling the female and then butting her in the genital region. Another curious aspect of their courtship included a maneuver I refer to as "head-bashing." The two fish would position themselves at right (90°) angles from each other and then dash forward with operculars flared and crash mouth to mouth, scull backward, and repeat the bashing 4-6 times per episode! Given the size and extreme development of the jaws, lip-locking was impossible. Instead, they often "made baskets;" opened their mouth to full extension, faced each other mouth to mouth and pushed themselves back and forth (Figure 9).
These flurries of courtship activity were separated by episodes of substrate cleaning. Both sexes participated in repeatedly cleaning the various horizontal slates, smooth rocks, and clay caves offered them. Again, the unique mouth was utilized: Partial baskets were rapidly and repeatedly expressed as the fish appeared to nibble the surface (Figure 10).
As courtship proceeded, the color of both individuals darkened dramatically, both expressing faint Aequidens-like vertical bars on the body and dark interorbital facial stripes, and the huge eyes became brilliant red. Intermittent courtship and cleaning behaviors proceeded with no damage to either fish (who were obviously both ripe) for five days: clearly a case of courtus interruptus. During this time a fifty percent water change was done, the temperature dropped to 84°, held there for 24 hours, and then hiked back up to 95°F. (again a strategy that had proven effective with Acarichthys heckelii). Finally the female's tube emerged fully. It was huge (1/8 inch diameter) and resembled a pencil eraser, and it became clear that spawning was imminent. Cleaning behavior increased dramatically and the male's tube descended.
They spawned in the late afternoon in my absence. After cleaning every surface vigorously except the one they chose, they pasted their eggs onto the curved surface of a broken clay flowerpot which was positioned, unfortunately, just under the return of a small (120 gph) power filter. The eggs were small, ovoid (1x0.5mm), clear amber in color, and attached by their long axis in a huge plaque numbering in excess of one thousand eggs that covered most of the 6 x 4 inch flowerpot shard (Figure 11). Upon discovery I immediately turned off the power filter and slowly reduced the temperature to 86°F. The parents maintained a rather sedentary vigil on either side of the pot, the female occasionally fanning the eggs gently with pectoral and anal fins, and both occasionally threatening the few remaining goldfish or me.
Within 2-3 hours of their discovery, the eggs began turning milk white and I, of course, panicked. Viable Acarichthys heckelii eggs are similarly opaque (Leibel 1984) and those of the Oscar, Astronotus ocellatus, initially clear, likewise turn milky white as they develop (Eckstein, personal communication). More and more eggs turned white: By six hours post-spawn 50-60% were opaque, by twelve hours post-spawn nearly all had turned and they began to drop from the pot and roll loose on the substrate (once again with precedence in Acarichthys heckelii). Were these viable?
By 24 hours post-spawn, nearly all the white eggs had fallen off the pot assisted by the gentle fanning and mouthing of the female. These still rolled loosely and no fungus was in evidence. Perhaps 50-100 clear amber eggs were still attached to the pot. I siphoned some of each and inspected them under the microscope: The clear amber eggs had embryonated but the opaque white eggs showed no signs of development. These later fungused. The parents continued to guard the viable amber eggs for an additional four days as most gradually turned white and rolled off the pot. Eventually two hatched, wriggled, swam, but would not take food and died. Although disappointed, I concluded that the male was at least fertile, the pair compatible, and that the power filter, to which I attributed the demise of the eggs, had to go.
The fish were separated and fed ad libitum on goldfish and occasional large krill. Roughly two months later, in early March, the female began dancing again for her consort. I pulled the divider, increased the temperature as before, and watched the same courtus interruptus behavior. They once again cleaned everything in sight and then chose the same broken flowerpot to hold their eggs which again numbered about one thousand. They were model parents, the female gently fanning and mouthing, and the male guarding the perimeter often with his consort's assistance. This time the majority of the eggs remained clear amber, the white inviable ones rolling accommodatingly off the pot, and hatched in 72-96 hours at 86°F. (30°C). The fry initially remained attached to the clay surface via mucoid secretions from their hatching glands located on top of their heads, and then slowly were spat by the female into a compact ball of fry adhering to each other. They wriggled helplessly for four days as a brown ball absorbing their yolk supplies and then swam free. The free-swimming fry were small but too tiny, easily handling microworms for the first 2-3 days and then graduating to newly-hatched Artemia nauplii. In color and shape they resembled fry of Nannacara anomala, the golden-eye dwarf cichlid from Guyana. They were light brown in base coloration with a dark brown stripe along either side and their heads were squarish with conspicuous hatching glands on the top surface. They grew quickly and after 10 days post-hatch lengthened and became more fish-like as the hatching glands regressed.
Most of the free-swimming fry were removed from the parents (placed in a 5 gallon tank nested in the four foot 30 gallon breeder in which they had been spawned) but they continued to guard those fry that remained. The parents threatened onlookers by opercular flaring and by rushing the front glass with basket mouth extended, the female often participating, but only after warning the fry of danger by typical fin-flicking signals. She would pull both ventrals in towards her body while simultaneously lowering dorsal and anal fins and then rapidly "flicking" them back and forth several times in succession. The fry were fairly unresponsive.
The parents were removed shortly thereafter and the 800 (roughly) raised in the 30 gallon breeding tank. Losses were minimal and the fry grew quickly on a diet of Artemia nauplii. By two weeks post-hatch they more closely resembled jewelfish fry (Hemichromis guttatus) retaining the dark horizontal stripe but becoming increasingly chunky and torpediform (3'16-7/32 inch TL; 4.8-5.6 mm). Shortly thereafter, the lateral stripes broke up, the characteristic mid-lateral blotch developed, the body filled out, and they began eating off the bottom, something their wild parents never had done. Hatching brine shrimp to satisfy their ravenous appetites became a problem (frankly, I'm lazy), but the size of the mouths on these baby fish and their obvious willingness to eat off the bottom suggested that finely-chopped frozen foods might suffice. They eagerly snapped up frozen bloodworms minced with a razor blade and one week later were taking frozen adult brine shrimp. Their mouths, eyes, and bellies were unbelievable. At this juncture, their growth become non-uniform, the largest reaching 3/8 inch (TL) a mere 3 weeks post hatch and now decidedly nassa-like in body shape. The larger ones continued their growth spurt, several reaching 1 inch (TL) 10 weeks post-hatch with the average size more nearly I/2-3/4 inch (TL). The larger got larger at the expense of the smaller (they are gape and suck predators) and soon the population had dwindled to 2-3 hundred, a more realistic number to raise and distribute. Since many cichlids show sexually-related size dimorphism at early age, a number of the smaller individuals were separated from the shoal to ensure females. At about 3/4-1 inch (TL), the juvenile nassa developed the characteristic adult coloration and markings (Figure 5), and began, unlike their wild parents, to accept shredded dried krill and other prepared foods. They continue to grow rapidly and steadily and should reach sexual maturity in two years. It remains to be seen whether the tank-raised generation will be less belligerent and more social than their wild counterparts and whether their captive propagation will become easier as is apparently the case for captive spawned Acarichthys heckelii (Leibel 1984) which are now two years old and spawning peaceably in the tanks of Dewey and Delores Schehr, Detroit Michigan.
Figure 8: Male Acaronia nassa (6 inch TL)Photo by Wayne S. Leibel.
Figure 9: A pair of Acaronia nassa "making baskets". Unable to lip-lock on account of their highly protusive mouths, this pair completes its prenuptial jousts by pushing each other around the tank with fully extended mouths. Photo by Wayne S. Leibel.
Figure 10: The pair cleans a posible egg receptacle just prior to spawning.Photo by Wayne S. Leibel.
Figure 11: Nearly 1000 ovoid, amber eggs were deposited on this 6" x 4" flowerpot shard.Photo by Wayne S. Leibel.
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© Copyright 1997 Wayne Leibel, all rights reserved
Leibel, Wayne. (August 01, 1997). "Basketmouth Cichlid: Acaronia nassa (Heckel 1840), The". Cichlid Room Companion. Abgerufen am September 18, 2020, von: https://cichlidae.com/article.php?id=58&lang=de.