Descrizione originale come Thorichthys helleri meeki:
- Brind, Walter L.. 1918. "A new subspecies of Thorichthys helleri". Aquatic Life. 3 (8); pp. 119-120 (crc00274)
- Cichlasoma hyorhynchum Hubbs, 1935, con località tipo in Río San Pedro de Mártir, a tributarie of Río Usumacinta, at El Paso de los Caballos, Petén, Guatemala. Determinatore: Hasse, 1981
- Thorichthys helleri meeki, Brind, 1918:119, combinazione originale
- Cichlasoma hyorhynchum, Hubbs, 1935, sinonimo junior (by Hasse, 1981)
- Cichlasoma meeki, Miller et al., 1961, nuova combinazione
- Thorichthys meeki, Kullander, 1996, nuova combinazione
Etimologia: The name was given by Walter L. Brind to honor the noted early 20th century American (Born in Ohio) zoologist Seth Eugene Meek (1859-1914), a disciple of David Starr Jordan. Seth Eugene Meek made important fish collections in the United States, México and Central America. As a result of his surveys he described numerous fish species and genera, including the genus Thorichthys. He is well known for his papers on Mexican and Panamanian fish.
Nomi comuni: Boca de fuego (Messico); Chonga; Firemouth cichlid (Stati Uniti); Scarlet chanchito (Stati Uniti).
Holotype Stored at the Smithsonian Institution National Museum of Natural History (Formerly United States National Museum) with code USNM 79243 (previously USNM 61490). According to Brind in the original description (1918), 265 specimens from which the holotype was selected were collected in May, 1917 by a French sailor in shallow reaches of a river near the port of Progreso in the northern part of the Yucatan peninsula, and sold to him in New York. Those were distributed among aquarians.
Diagnosi: Walter Brind mentions that the fish shows a presence of red, not mentioned by Meek (1904) when referring to Thorichthys helleri in the paper describing the genus Thorichthys. Unlike it, the fish shows "a brilliant scarlet suffusion and striping extends from the throat and lower gill covers back and beyond the extremities of the pectoral fins, otherwise the coloration is much as the type (Thorichthys helleri).".
Dimensione: Although Brind (1918) mentions that Thorichthys meeki reaches a length of six inches (15.2 centimeters) (I assume he is talking total length), specimens of such large size should actually be quite rare, being more common for them to reach a maximum size of 12 cm TL for males (not counting fin threads), and eight for females. Correspondingly, my aquarium raised specimens have never growth larger than this size. Even this large 12 cm. specimens are rare in the wild.
Dimorfismo sessuale: Thorichthys meeki does not show a noticeable sexual dimorphism, males grow larger and show larger threads in the unpaired fins. Females often have larger bellies.
Località tipo: Near Progreso, Yucutan, Mexico.
Distribuzione: Thorichthys meeki has a wide distribution, it can be found in the Mexican Gulf slope from the Tonala River in the north eastern part of the Tehuantepec Isthmus east to tributaries of the lower Grijalva river in Tabasco, and north to the upper part of the Yucatán peninsula (North Latitudes 17°30’ to 22°30’, West longitudes 88° to 93°). This includes Tonala, Pichucalco, Oxolatlan and Teapa rivers, the lagoons around the lower Grijalva and Usumacinta basin, the Tulija and Usumacinta and its affluents including Chancala, La Pasion, Lacantun, San Pedro Rivers. Also in Chompán, Candelaria, and the last northern Yucatán major river, the Champotón. Beyond this point north it will be found in most sinkholes (Cenotes) over the western and northern part of the peninsula. This fish will just inhabits lowlands up to about 150 mosl. In upper areas of the mentioned rivers with clear water T. meeki is scarce and only found in some backwater areas.
T. meeki is also found in the eastern part of the Yucatan Peninsula from sinkholes in the Sian Ka'an Biosphere Reserve south of Tulum to the northern part of Belize south to the Belize River. In this area T. meeki is found in clear water rivers and lakes, in opposition to habitats west of the Yucatan Peninsula.
There are records (Lee et al, 1980) that T. meeki has been established in a small area in the southern part of the Peninsula of Florida, most likely deriving from escapees from aquarium fish farms.
T. meeki exhibits a good degree of variability within its range, both morphologically as well as in color pattern. The most colorful individuals are likely found in the pools of the lower Grijalva in the state of Tabasco, which show an intense red in the lower part of the head and belly. The red is also present in the unpaired fins and in a lesser degree on the back of the body. Individuals in the upper Usumacinta area apparently grow a little bigger than those found in pools in the lower Gijalva- Usumacinta. Populations in the Caribbean slope show a yellowish tint on the body and the red is not as intense as those of the Gulf slope, sometimes being as pale as orange.
Località: Mopan River (Guatemala, natale), Roaring creek (Belize, natale), White Water Laggon (Belize, natale), Candelaria River (Messico, natale), Champoton River (Messico, natale), Carrizales River (Messico, natale), Illusions Lagoon (Messico, undefined), Teapa River (Messico, natale), Caobas Lagoon (Messico, natale), Cenote Azul (Messico, natale), Dulce River (Messico, natale), Lake Bacalar (Messico, natale), Ucum River (Messico, natale), Mamantel (Messico, natale), Noh Lagoon (Messico, natale), Mizol-Ha River (Messico, natale), Lake la Gloria (Guatemala, undefined), Lake Lachuá (Guatemala, natale), San Juan River (Guatemala, undefined), San Pedro River (Guatemala, natale), Subin River (Guatemala, undefined), El Remate (Messico, natale).
Habitat: Thorichthys meeki mainly inhabits stagnant overflow shallow lagoons formed during the rainy season, as those found in the lower part of Grijalva and Usumacinta Rivers. They also inhabit backwaters or areas with slow flow and muddy bottom in the rivers in its range. However, a few populations are found in clear water sinkholes, springs and rivers, especially in the eastern part of the Yucatan Peninsula, in northern Belize and other Mexican habitats.
Some of the lagoons where this fish inhabits are permanent and a few dry up in the dry season. In these lagoons T. meeki occur in tremendous densities with other fishes. Thorichthys meeki is always one of the most abundant cichlids in its habitat.
Water throughout the T. meeki range is rather alkaline with a moderate hardness, normally over 8 GH with a pH over 7.5. Some lagoons near the sea have a slight saline content. I was surprised however when I saw a few individuals in an apparently hyper-saline spring in the upper part of the Yucatan Peninsula, at Celestum, together with fish well know to have strong saline resistance.
Water temperature is variable within the approximate range 22 to 30°C, having the warmer range at the late part of the dry season from December to May. Rains bring a decrease in temperature in the T. meeki range.
Normally, the water bodies that T. meeki inhabit are characterized by low visibility, shallowness and soft substrate, normally composed of mud and layers of fallen leaves. The edges of pools normally have bog vegetation as well as grass. Some driftwood could also be found. Vegetation is normally absent but water lilies Nymphaea sp. and water hyacinths Euchornia sp. are present to some degree.
Associated fish fauna include the cichlids: Thorichthys pasionis, T. helleri (in small numbers), Astatheros robertsoni, 'Cichlasoma' salvini, 'C.' urophthalmus, Rocio octofasciata, Vieja heterospila (In small numbers), Parachromis friedrichsthalii, P. managuensis, Petenia splendida, other families include Characidae; Astyanax aeneus and Hyphessobrycon compressus, Cupleidae; Dorosoma anale and D. petenensis; Pimelodidae; Rhamdia guatemalensis and R. laticauda, Ariidae; Arius aguadulce. Poeciliidae; Poecilia petenensis, Gambusia sexradiata, Belonesox belizanus, Xiphophorus maculatus, Poecilia mexicana. Rivulidae; Rivulus tenuis. Symbranchidae; Ophisternon aenigmaticum. Lepisostidae; Lepisosteus tropicus and others.
Conservazione: Thorichthys meeki è valutata dalle organizzazioni internazionali di salvaguardia delle specie a rischio come (LC) basso rischio (2018).
Alimentazione: Thorichthys meeki feeds on the soft substrate in its range, where they pick their food upon inspecting the substrate with their pointed snout. Most of its diet is apparently formed by invertebrates, mainly copepods and cladocerans, although a small content of fish and filamentous algae (up to 29%) has been found in stomach examinations, overall, T. meeki can be considered a zooplankton eater (Valtierra-Vega et al, 2000). T. meeki feeds in groups and the feeding behavior apparently consumes most of its time in the natural habitat, according to my observations of non-breeding individuals. Dominant fish forage in the most profitable areas of habitat, while sub-dominant fish avoid confrontation and inspect the second most productive areas (Hodapp & Frey, 1982).
Riproduzione: Reproductive pairs of Thorichthys meeki form mainly from March to May during the rainy season, although in more stable habitats like Laguna Bacalar they may form all around the year (Neil, 1984). There are two ways in which pairs form. Either a male selects a territory that offers certain cover near a hard surface and courts passing females, who usually respond to some degree to their courtship or pairs are formed previously to the establishment of territories.
In the first case males select a spot that offers cover to some degree, so they can focus their territory defense in the area not covered. Males stay in their territories and assume a slightly head standing pose (some 10-30 degrees) with fully extended fins, passing females are then courted by shivering and displaying to them, some decide to circle the males extending her fins while the male responds to this standing in the center of territory and extending his fins back to the female. In many cases the females decide to leave the territory after this brief courting but they may return, or some female may decide to stay, in which case they form a pair.
In the second occurrence T. meeki pairs form in their feeding territories and pairs decide to wander around for some time until a territory has been chosen. This way to form a territory is however less frequent than males establishing territories (Neil, 1984).
In either case males or pairs defend their territories from intruders or neighboring pairs extending their gular pouches forward and making small runs in the intruder’s direction. The black spots present at the sides of the head of Thorichthys (except in T. callolepis) show as bigger more separated eyes when the gills are opened, making the fish look bigger (Radesater & Ferro, 1979).
Breeding areas for T. meeki tend to become highly populated, and pairs compete strongly for territories with neighboring pairs, with both individuals incurring in frequent encounters (Neil, 1983), but rarely with any damage done to any individual.
Males and females extend their genital tubes some hours prior to the spawning act after they have vigorously cleaned the spawning surface using their mouths. Females make small runs close to the spawning surface depositing rows of clear amber colored eggs. The female moves aside while the male follows the path made by the female, fertilizing the eggs. This ritualized behavior repeats until the around two hundred eggs 1.7 mm in length (Coleman, 1998) have been deposited.
T. meeki pairs choose a rock crevice (if available) to deposit their eggs. Some pairs will choose a sunken tree leaf instead. I have noticed that T. meeki eggs are widely separated from each other, compared to other Thorichthys species, perhaps as a way to make more oxygen available to them in the low oxygen areas of its habitat.
Eggs, fanned by the pectoral fins of the female, take around 48 hours to hatch under aquarium conditions, by this time the pair has dug several small pits around the spawning area, wrigglers are carefully transported in the mouth by the pair to one of the pits, and changed from pit subsequently, perhaps as a way to fool the nocturnal catfish Rhamdia by distributing the eggs smell in several pits, making them harder to be found. In the aquarium it takes five days for the wrigglers to have consumed their heavy yolk sac and be able to swim. It may be two or three weeks after the establishment of the territory for the fry to become free swimming (Neil, 1984).
Once free swimming, fry are guarded closely by parents, guiding them with spasmodic movements of their body and the rapidly opening and closing of their fins. As in other Thorichthys species it is the female who stays just on top of the wrigglers, while the male guides the family movements and chases intruders away.
Parental care in T. meeki may last for up to three months (Neil, 1984), when the fry are large enough (about 15-20 mm in length) and desert their parents. During parental care, the pair coordinate very well in guarding the clutch of babies. Any distraction or the loss of one of the pair members, may quickly result in the babies being eaten by a predator, specially the vicious wandering Astyanax aeneus Characinids, ubiquitous in the habitat. Single parents have very a small possibility to raise a baby clutch to independent size.
It is common to find small Thorichthys near the shores of the habitat, normally among grass or present bog vegetation. When bigger (around 4 cm) they join feeding groups in the open.
Aquariofilia: Aquarium keeping of Thorichthys meeki, the fire-mouth cichlid, has been popular since their appearance in the aquarium hobby, over eighty years ago.
T. meeki are not very aggressive and are very beautiful cichlids that can be easily kept in the home aquarium. They require tanks not as large as most Central American cichlids, 250 liters, at least 1.20 meters long. These tanks being most of the time good enough for a group of them. Always choose larger surface over higher tanks (area is more important than height). When aquascaping, it is better to match their natural surroundings according to what I have described above, fine sand substrate (avoid mud though) and plenty of cover being best. This fish does much better when kept in groups. It's always better for them to look a little crowded to distribute their aggressiveness and enhance a more natural behavior. Dither fish are also an important part of the environment that we should provide. T. meeki do well with large Poeciilids (very small ones are eaten under aquarium conditions) as well as with many other similar not aggressive but fast moving fishes. In spite of their cichlid aggressiveness, given the right size aquarium, the fire-mouth ignore fishes that do not pose direct competition to them.
The Fire-mouth greedily eat most food offered, but although carnivorous, try to avoid offering them warm blooded animal meat, something that can usually cause them digestion problems that can lead them to death.
One aspect of importance to T. meeki well-being is to watch the aquarium water temperature; Thorichthys in my experience seem to be as prone to suffer from warm water as they are to cold water. We aquarists sometimes tend to forget the effects of warmer water, in Thorichthys, long exposure to water temperatures of 28 Celsius or warmer apparently lead to crooked fins and eventually death, T. meeki seems to be less prone to this situation that other Thorichthys species though, as are used to warmer natural temperatures and seem to withstand better this condition.
Commenti: Apparently, the Thorichthys meeki variant popular in the aquarium hobby for many years has been perhaps not the most colorful one. It is more likely the one found in the upper part of Yucatan peninsula, the place they originated for the aquarium trade more than eighty years ago. Nowadays, the most colorful populations from around the city of Villahermosa are getting more and more available, which assures a place of this cichlid in the interest of cichlid keepers worldwide for years to come.
Another aspect to consider is the evaluation of the older taxa Thorichthys affinis, which seems to be just a geographical variety of the Fire-mouth cichlid in every aspect. Those traits that we use to distinguish T. affinis from T. meeki, like the slightly more elongated body, the slightly convex upper head profile, the less intense red on the body, are in fact present in all populations of T. meeki in the eastern part of the Yucatan Peninsula, most likely, T. meeki is just a junior synonym of Thorichthys affinis.
In regards to the variability of T. meeki it has been suggested that some potential new species are awaiting to be described, one particular population is the orange colored population around Lake Bacalar (Schmitter-Soto, 1998). We should take into consideration that T. meeki as much as any organism with such a large distribution range should have some variability, which T. meeki exhibits throughout its range. I believe that we get nothing of value starting a boundless splitting for T. meeki as it has been recently done with other American cichlid species.
Although much has been studied about the natural history of this fascinating little cichlid, much remains to be learned, as it is their relationship with the sympatric Thorichthys pasionis, with which the fire-mouth cichlid keeps and obscure link. While both species can be found together (always in the case of Thorichthys pasionis), one year one species showing bigger numbers than the other and several years later apparently the opposite, they apparently do not hybridize in a way that poses a danger to the species stability. What is the purpose this seemingly complementary relationship?.
- Brind, Walter L.. 1918. "A new subspecies of Thorichthys helleri". Aquatic Life. 3 (8); pp. 119-120 (crc00274)
- Coleman, Ron & A. P. Galvani. 1998. "Egg size determines offspring size in neotropical cichlid fishes (Teleostei: Cichlidae)". Copeia (crc01251)
- Hasse, J. J.. 1981. "Characters, synonymy, and distribution of the middle American cichlid fish Cichlasoma meeki.". Copeia. pp. 210–212 (crc02490) (riassunto)
- Hodapp, Antoinette & F. Dennis. 1982. "Optimal foraging by Firemouth Cichlids, Cichlasoma meeki, in a social context". Animal Behaviour (crc03991)
- Hubbs, Carl Leavitt. 1935. "Fresh-water fishes collected in British Honduras and Guatemala". Miscellaneous Publications, Museum of Zoology, University of Michigan. (n. 28); pp. 13-15 (crc00252)
- Kullander, Sven. 1996. "Heroina isonycterina, a new species of cichlid fish from Western Amazonia, with comments on cichlasomine systematics". Ichthyological Explorations of Freshwaters. v. 7(n. 2), pp. 149-172 (crc01223) (riassunto)
- Miller, Robert Rush & B.C. Nelson. 1961. "Variation, life colors, and ecology of Cichlasoma callolepis, a cichlid fish from Southern Mexico, with a discussion of the Thorichthys Species Group". Occasional Papers of the Museum of Zoology, University of Michigan. (n. 622), pp. 9 (crc01100)
- Neil Susan .J.. 1984. "Color pattern variability and behavioral correlates in the firemouth cichlid, Cichlasoma meeki.". Copeia (crc02491)
- Neil Susan .J.. 1984. "Field studies of the behavioral ecology and agonistic behavior of Cichlasoma meeki (Pisces: Cichlidae)". Environmental Biology of Fishes (crc03990)
- Neil, Susan J. 1983. "Contest for space in breeding Cichlasoma meeki, the role of resource holding potential". Behavior (crc03992)
- Neil, Susan J. 1983. "Contest for space in breeding Cichlasoma meeki, the use of increased apparent size display". Behavior (crc03993)
- Radesater, T. & A. Ferno. 1979. "On the function of the ‘eye-spots’ in agonistic behaviour in the fire-mouth cichlid (Cichlasoma meeki)". Behavioural Processes (crc02495)
- Valtierra-Vega, Maria Teresa & J. J. Schmitter-Soto. 2000. "Hábitos alimentarios de las mojarras (Perciformes: Cichlidae) de la laguna Caobas, Quintana Roo, México". Revista de Biologia Tropical (crc01505) (riassunto)
Artigas Azas, Juan Miguel. (novembre 24, 2011). "Thorichthys meeki (Brind, 1918)". Cichlid Room Companion. URL consultato in data novembre 29, 2020, da: https://cichlidae.com/species.php?id=248&lang=it. (crc10821)