Wayne Leibel, 2003
Cichlid Room Companion

Of Pickled Fish and Ichthyological Sleuthing: A Primer For the Advanced Aquarist.. Part I: The Whys and Wherefores of Scientific Nomenclature

By , 1985. image

Classification: Taxonomy and phylogeny.

(This article was originally published in Freshwater and Marine Aquarium Magazine, Jan-85 pp. 34-43. It is here reproduced with the permission of author Dr. Wayne S. Leibel.).


Although the satisfaction of successfully maintaining and spawning fish remains a major component of my continued fascination and involvement with the aquarium hobby, of late my growing obsession of precisely establishing the identity of the fish I acquire and keep seems to be getting the upper hand. This orientation has deep roots: I remember hours spent pouring over various hobby-oriented fish compendia as a kid trying to match my newest acquisitions to published, labeled photos. This attempt was often in vain given the incompleteness and often downright inaccuracy of most of the aquarium encyclopedias of the time (1950-60s). And although the explosive growth of the aquarium hobby in the 60s and 70s was paralleled by the proliferation of a variety of more or less complete and worthwhile publications (Sterba 1966, the various specialty texts like Goldstein's 1973 Cichlids of the World, Scheel's 1968 Rivulins, etc., and even Axelrod's 1980 immensely improved expanded edition of Exotic Tropical Fish, for example), in many cases even these are insufficient to identify the oddball specimens that are sporadically imported, or which have never before reached the aquarium hobby.

Geophagus steindachneri
Figure 1: The aquarium Reh Hump Eartheater, Geophagus steindachneri, young male (5 inch TL). Photo by Gene Aldrige, Jr..

Geophagus pellegrini
Figure 2: Geophagus pellegrini, inmature specimens: female above, male (5 inch TL) below. Fish collected in Panama by Dan Fromm and Dale Weber. Photo by Wayne S. Leibel.

Geophagus crassilabrus
Figure 3: Geophagus crassilabrus, wild caught male from Panama collected by Ian Sellick and Teresa Townshend. Photo by Ian Sellick.

Geophagus steindachneri
Figure 4: Geophagus steindachneri, color variant. Compare this male Red Hump with the most commonly available morph. A golden strain (oligomelanic) is also available in the hobby. Photo by Ian Sellick.

There are other, more persuasive reasons why pin-pointing the identity of the fish you keep is a valuable, if not mandatory, goal. (Obsessiveness in and of itself is just weird!) The first of these is a selfish reason: when I order a fish from a breeder through the mail sight unseen, I want to receive the exact species I had in mind. A recent list of Geophagus species recorded in a national Breeders Award Program had separate entries for each of the following fishes: G. crassilabrus, G. pellegrini, G. hondae, and G. steindachneri. In fact, I am willing to bet that all four entries refer to the Red Hump eartheater, Geophagus steindachneri (Fig. 1). I make this assertion knowing (1) that the name G. hondae is a junior synonym of the "common" Red Hump, G. steindachneri (Gosse and Kullander, 1981) despite Axelrod's entry (1980, p. 688) under that now invalid nomen, and (2) that pellegrini and G. crassilabrus, two distinct and valid species have not, to my knowledge, been commercially imported or distributed outside of occasional contaminants of the former in shipments from Colombia (Figs. 2 & 3). To my knowledge, only Dan Fromm and a very few aquarists he has shared them with are maintaining captive populations of true pellegrini and crassilabrus in this country. Note also, the name pellegrini was the name first applied to the Red Hump in the trade, further compounding the problem. I would drive several hours to acquire true crassilabrus or pellegrini but I would be pretty disappointed if a blind mail order for either yielded a bag of common Red Humps (with all due respect to these delightful animals!).

A second reason hinges on the current status of organismal biology in general and ichthyology specifically in modern academe. With the abysmal employment and funding opportunities for classical ichthyologists, advances in modern taxonomy and phylogenetics will depend more and more on avocational naturalists (as historically it did two hundred or more years ago). What advanced hobbyists have to contribute to the scientific effort is their keen observational abilities and their skill in inducing captive spawning. Behavioral ecologists George Barlow or Miles Keenleyside, as good as they are and as many graduate students as they might have, are incapable of completely inventorying the diversity of extant cichlid behavior. Hobbyist-generated observation recorded in local or national hobby publications is a gold-mine of information providing valuable leads for academic biologists (if and 34 only if) the fish whose behavior is observed and described are accurately identified. As an active member of the Geophagus/Aequidens Study Group of the American Cichlid Association, I have become increasingly concerned with the proper identification of species from these two and closely related genera. It is part of our goal as a study group to establish correct identifications of species currently circulating in the hobby and to document them photographically for the record in publications like Buntbarsche Bulletin and in slide sets made available to the general membership of the ACA, thereby correcting errors or omissions in the available hobby bibles. An arcane and esoteric enterprise, perhaps, but a logical extension of the hobby and of great interest to any serious hobbyist who demands the correct identification of the fish he or she keeps. It is the purpose of this article to simply explain the nuts and bolts of scientific nomenclature, and to share with other, similarly obsessed advanced aquarists strategy for identifying those uncommon specimens for which no reliable hobby-based identification exists.

Accepting and Understanding the Limitations of Hobby Compendia

Words set in type (these included) take on an air of authority and inviolateness which has little to do with their content. This is particularly true with the various hobby bibles used by aquarists to identify their charges. Many of the so-called "experts" that have authored these great works are actually quite knowledgeable and accurate in their dogmatic pronouncements, but just as many are not. A comparative stroll through Innes (1938), Sterba (1966), Axelrod (1980), or Hoedemann (1975) with reference to fish such as Apistogramma cacatuoides, Satanoperca acuticeps, or Nannacara taenia, for example, will produce some amazingly discordant photographic opinions as to which living animals should bear which identification. And the problem is probably not restricted to neotropical cichlids, although my own spotty knowledge and interest in families other than Cichlidae leave me incapable of similar chapter/verse citation of other glaring discrepancies. All our hobby heros have clay feet to a greater or lesser extent, and that realization is the cause for some celebration as it leaves considerable roorn for the advanced hobbyist to make lasting and important contributions to the correct identification of the various species that are imported and move through the hobby. Acknowledging and accepting the limitations of the existing literature is the first step toward resolving some of the ID problems.

The reason for the inaccuracies and discrepancies in the identification of living fishes rests with the nature of the road maps available to the "experts" for use in pin-pointing the identity of living fishes. The original scientific descriptions (nuts and bolts of the process to be detailed below) generally deal only in measurable characters: fin and scale counts (meristics), body proportions (morphometrics), tooth and gill raker number and shape (etc.), and not coloration. Any allusion to the latter is usually coloration in preservative. Only rarely will the topic of life coloration be broached, and these infrequent descriptions are largely of newly-netted, stressed fish expressing a distinctive (and often generically-shared; e.g., Aequidens vertical bars) fright pattern, and are, therefore, of little use unless you net, bag, and shake your hapless aquarium friend. In fact, many of the earlier published rock-propped stiffs or newly-netted, petrified fish in phototank shots are useless for identification for the same reasons. On this basis alone, the "expert's" errors become quite understandable and forgivable; they must try with the scanty information on hand from dead pickled specimens, to extrapolate the shape and coloration of living aquarium specimens. It just isn't that easy!

Compounding the problem are the confusions that exist in the scientific literature itself: multiple independent descriptions of the same fish netted at different localities by different collectors and described by young taxonomists eager to immortalize colleagues, patrons, and even self. Many of the apparently valid scientific species are, unfortunately, red-herrings and either invalid or synonymizable (i.e., referable to a previously described species, see below). All these caveats aside, the process of tracking down the original literature and applying these descriptions to living aquarium fish is a delightful form of intellectual exercise with much to recommend it. Armed with a general understanding of taxonomic principals and a strategy for obtaining and utilizing published original descriptions, the challenge of correctly identifying fish is accessible to any serious hobbyist.

Taxonomy and Nomenclature: A Digression

Human beings from time immemorial have applied names to the organisms with which they shared the Earth. The sheer diversity of human languages and, hence, organismal names, however, rapidly became a serious impediment to cross-cultural communication. Even today, common Anglicanized names for fish often lead to misunderstanding; the name "flag cichlid," for example, is applied to at least two distinct fish, Aequidens curviceps and Mesonauta festivum, and forget "flag fish!" Medieval scholars solved the communication problem by substituting Latinized (the language of European scholarship) for vernacular names. The Swedish naturalist Carl von Linne (later self-proclaimed Carolus Linnaeus in deference to this scholarly convention) further standardized the science of naming organisms, taxonomy, by proposing a binomial system of nomenclature in his monumental Systema Naturae (1735). Whereas unwieldy Latin polynomials dominated the early biological treatises, Linnaeus proposed a convenient shorthand consisting of two nomina, the second naming the beast (species) and the first indicating relatedness with other, like, species (genus). Binomial Nomenclature is still the universally adopted system of naming organisms 250 years later.

What has changed over that same time span is our conception of "species." Originally, species referred to a group of organisms that were morphologically identical (i.e., looked the same) and new species names were erected for any newly-discovered organism that looked different from any others that had been previously described and named. In the heyday of taxonomy, the 1600-1800s, new species were described by the thousands as naturalists embarked upon expedition after expedition to the jungles of South America and Africa. Often "species" were described on the basis of a single specimen taken from a single locality. Moreover, the considerable morphological variability that exists in natural populations of a species was generally not recognized (e.g., consider the variable color and stature of Homo sapiens) and old and young individuals, male and female individuals of the same population (merely endpoints in the continuum) were often described as distinct species. This is not unlike describing the guppy over and over again by virtue of differences in coloration and finnage of different strains and sexes. Complicating this period of promiscuous naming was the fact that communication between naturalists so engaged was difficult. This resulted in multiple descriptions and different names for a single type of organism. More recent examination of many of these older "species" has proven them identical and thus synonymizable under the chronologically earlier name.


a. Caudal and Soft Dorsal Spotted
b. Dorsal fin (spiny rays) XV or XVI, rarely XVII. One scale between lateral line and soft dorsal. No dark bar below eye, even in youngest... steindachneri Eigenmann & Hildebrande.

aa. Caudal and soft dorsal uniform.
c. Dorsal fin generally XV or XVI; two scales between lateral line and soft dorsal...crassilabrus Steindachner.

cc. Dorsal fin generally XVII, sometimes XVIII; one scale between lateral line and soft dorsal; a dusk shade from eye to angle of preopercle, well marked in young; some of thelateral bands of the male continued on thespinuous dorsal, especially in specimens from the Atrato Basin...pellegrini Regan.
Figure 5: A dichotomus key for the "Red Hump" species complex after C.H. Eigenmann, 1942, "The Fishes of Western South America," Memoirs of the Carnegie Museum, Volume 9, page 195.

Simply designating species was not the sole occupation of the early naturalist. Implicit in the cataloguing of any large and diverse group of items in an ordering of that inventory in terms of relatedness, an exercise more properly known as systematics. Linnaeus once again standardized the science by suggesting a hierarchical series of pigeonholes, or categories, into which related species might be placed together. Thus, related species are grouped into genera (singular: genus), related genera into families, families into orders, orders into classes, classes into phyla (singular: phylum) and phyla into kingdoms. The Red Hump Eartheater of the second paragraph in this essay, for example, Geophagus steindachneri, is a member of the family Cichlidae, order Perciformes (Perch-like fishes), class Osteichthyes (bony fishes), phylum Chordata (with a rigid spinal chord), kingdom Animalia. Such groupings are generally based on characters that are shared between organisms. Members of the cichlid genus Geophagus, for example, all have lobed gill arches with numerous gill rakers (the better to sift sand with!). They share this character (trait) with the closely related genus Apistogramma, but receive distinct generic status owing to a second character not shared; the upper lateral line of Apistogramma species is separated from the base of the dorsal fin by less than 2½ rows of scales, whereas all Geophagus have lateral lines situated on their flanks well below this 2½ scale row cut-off. Both genera, however, are grouped as cichlids (family Cichlidae) because they share other, more generalized characters (e.g., spiny and soft rays of dorsal and anal, single pair of nostrils, divided lateral line). The usefulness of systematic classification such as this has been simplified by the creation of dichotomous keys that define each of the various taxons (specific categories) indicating what characters are shared by individuals lumped into a given category. An example for our "Red Hump " Geophagus appears in Figure 5. One can "key-out" an unidentified species simply by applying the criteria described in the key, making decisions as to their presence, or absence, in the specimen in question, and proceeding through the key as so directed by these decisions.

Consequent to Darwin's (1859) magnum opus The Origin of Species by Means of Natural Selection, and the eventual but embittered embracing of its major concepts, our notion of "species" itself evolved. Implicit in the idea of morphological homogeneity is genetic homogeneity. A species, by extension, was a population of organisms that interbred freely (sharing their genes) but which was reproductively isolated from all other species populations. Biological species, in the truest sense of the concept, were operationally defined. Moreover, species were not immutable units but, rather, subjected to changing selective pressures of the environment and, thus, constantly changing genetically and morphologically in time. "Relatedness," the lumping of like-species into higher order taxa, took on added meaning along the dimension of evolutionary time. Which species was derived from which evolutionarily? Which traits are primitive and which advanced and hence derived? Can we trace the evolutionary lineages of the various species? The science of phylogenetics addresses these dynamic and difficult questions of evolutionary relatedness (phylogeny). The debate over what a species is and how one proceeds to reconstruct the phylogeny of an organismal cluster is far from resolved.

While the aquarist can certainly contribute greatly to an appreciation of what fish constitute biological species by attempted inter-specific breeding in captivity, the simple identification of fish ignores the biological species debate and proceeds from the earliest conception of species, that on which most of the original descriptions were based, the morphological species.

Taxonomic Conventions: Standardizing the Process of Naming Species

Whereas much of early taxonomic work was haphazard and insufficiently documented, the process of designating new species has been standardized by convention to promote universality in the scientific naming of organisms and to ensure that each species is unique and distinct. Towards this end, zoologists from Europe, Russia, and America drafted formal rules of nomenclature around the turn of the twentieth century. This International Code was first adopted in 1901 at the Fifth International Zoological Congress, and has undergone several major and minor modifications since that time. The text of the 1964 Revised Code, currently in usage, may be read in its entirety in Mayr (1969).

Aphyosemion bivittatum
Figure 6: Adult male Aphyosemion bivittatum from Kumba in the Cameroons. Photo by Anthony Terceira.

Aphyosemion bivittatum male
Figure 7: Adult male Aphyosemion bivittatum from Ekondo Titi. Photo by Anthony Terceira.

A. bivittatum male
Figure 8: Hybrid A. bivittatum male resulting from cross of Kumba male with Ekondo Titi female. Photo by Anthony Terceira.

In general, a taxonomist must proceed in regimented fashion to describe a new species. Assuming that the specimen can at least be keyed to an existing genus, the scientist must first mount an exhaustive literature search of previously described species. Most ichthyologists, keying species in their major area of interest (i.e., group of fishes) would have a complete and established library of primary sources already in their files. If the specimen in question does not satisfy the given species descriptions in the literature, the ichthyologist might consider the new specimens sufficiently different to warrant designation of a new species. How different is different enough? Some ichthyologists, those less conservative in their judgment of inter-populational variability, would be likely to create a new species name. Others, more cautious, might elect to refer the specimen to a designated species as an example of extreme variability (Fig. 4). The test, of course, is in the failed or successful interbreeding, but that's difficult to attempt with pickled specimens! Nowhere is the problem of splitting or lumping species more clearly demonstrated than in the subfamily Rivulinae, the killifish of the aquarium hobby. Fishes like Aphyosemion bivittatum or Aphyosemion gardneri, for example, exist in patchy, isolated populations of morphologically very different individuals (see Terceira and Slocum 1975). Although species-status was originally conferred on many of these (bivittatum, loennbergi, multicolor, splendopleurus, etc.), (see Figs. 6-8), the proof is in the fertile interspecific offspring produced in aquaria: many are referable to A. bivittatum. The situation is less clear for mbuna cichlids of Lake Malawi who, in the absence of conspecifics in the aquarium, will hybridize freely across specific and generic lines, but which, in the wild, normally choose the appropriate consort of the same species. The two examples above illustrate the difficulty in relegating a new morphologically-distinct fish to species status even in view of captive breeding data.

Having made the decision to create a new species for the specimen, the ichthyologist must describe this new species in a prescribed manner. The specimen must be measured and counted and characters which diverge from closely-related species in that genus noted. The latter (differential diagnosis) is particularly helpful to other workers who will not have access to pickled examples of the new species. A Latinized species name must be chosen which is not, or has not, been previously occupied (the situation is actually quite complex and stringently dictated by several Articles in the Code). The name may refer to a salient species character (crassilabrus = thick lips), the geographic locality of collection (hondae; after Honda, Columbia), or may honor a person (pellegrini, steindachneri; after Pellegrin, and Steindachner, famous French and German ichthyologists respectively), as long as the name is available. Obviously, complete familiarity with the nomenclatural history of the genus is necessary to avoid inadvertently selecting an unavailable, hence ultimately invalid name. The rolls of genus and species names are full of examples where name changes were later dictated owing to the choice of an unavailable (i.e., previously or currently used name) thus invalid nomen.

The species description, including complete diagnosis and name, is then published as a permanent record, usually in an internationally distributed and acknowledged journal, and the type specimen (holotype) that from which the published description is based, and additional collected material referable to the holotype (paratypes) are preserved and deposited in the collection of an established museum as a point of reference. Ichthyologists may request shipment of the holotype or paratypes from the museum for later study.

These rules apply to species described after 1931. The problem of earlier descriptions, the majority of named species, is a real and difficult one. Often the species description and diagnosis is terse and incomplete, or the new species name is merely mentioned tangentially or the animal figured in a publication with no supporting diagnosis. Many of these incomplete original descriptions were subsequently redescribed on the basis of more complete study of the holotype at later time by another ichthyologist intent on making sense of the earlier species. However, often holotypes do not exist: either they were never added to a museum collection or they have been subsequently lost. Such is the case for many of Heckel's cichlid type specimens deposited in the Berlin Museum and subsequently lost to bombing raids in the Second World War. In the loss or absence of the holotype, other specimens may be designated type specimens (neotype) in their place to provide a physical standard of comparison for later researchers.

Decisions as to the validity of such incomplete species descriptions are arbitrated and rendered by the International Commission on Zoological Nomenclature based on interpretation of the Code. One such situation revolved around the correct species name of the Red Hump Eartheater. Acceptance of the nomen hondae for this fish was affirmed by Gosse (1975) in his revision of the genus Geophagus, hence usage of this specific in the aquarium trade and in Axelrod's (1980) compendium. However, the nomen steindachneri was later judged the first and correct name for this fish on a hair-splitting point raised by several including Loiselle (1974). In a nut-shell, the nomen steindachneri appeared first in a checklist of Colombian fish authored by Eigenmann and Hildebrand in 1910, referable to a fish described by Steindachner in 1880 as a "Geophagus brasiliensis" which differed from the Brazilian holotype only in dorsal fin ray count. Steindachner (1880) never formally named this fish (i.e., designated it a new species) and Eigenmann and Hildebrande (1910) while naming it, never described it! Although the fish was later completely and correctly described by Regan (1912) and named hondae, the Commission has ruled, in fact, that Eigenmann and Hildebrande's (1910) terse reference constitutes a "description" by citing Steindachner's (1880) earlier commentary on it, and the name steindachneri has chronological precedence. So goes taxonomy and politics, alike! I heartily recommend articles by Loiselle (1974), Taphorn and Lilyestrom (1979), and Gosse and Kullander (1981), all of which appeared in Buntbarsche Bulletin, for a further elaboration of the hondae-steindachneri affair.

Taxonomy is Dynamic

It must be stressed that taxonomy is a dynamic science: the validity of species is always subject to challenge and, historically, revisions of "accepted" nomenclature and systematics is the rule. Luckily, such change occurs sporadically and in accord with the shifting interests of an ever-decreasing pool of professional ichthyologists, so that the hobby 'can absorb them easily enough. In this process, the original descriptions of species in a given genus are scrutinized and the holotypes or neotypes fished from their bottles and re-measured. Often, additional specimens will have been added to the museum collection over the years as additional sites are collected. This additional material from a diversity of geographic locations enables the taxonomist to gain increased insight into the normal, natural variability that exists in a species and often prompts lumping two or more specimens originally judged distinct species into a single species.

Satanoperca jurupari
Figure 9: Satanoperca jurupari, common Amazonian morph. Photo by Wayne S. Leibel.

Satanoperca jurupari
Figure 10: Satanoperca jurupari, bronze colombian morph. Goose (1975) elected to lump these two jurupari color variants as one species. Photo by Doug Smith.

Gymnogeophagus balzanii
Figure 11: Gymnogeophagus balzanii, mature male (7 inch TL). Type species of teh genus Gymnogeophagus split off from Geophagus by Goose (1975). Photo by Wayne S. Leibel.

Gymnogeophagus rabdothus
Figure 12: Gymnogeophagus rabdothus, mature male (4 inch TL). Although drastically different in overall appearence, both Gymnogeophagus rabdothus and G. balzanii share enough important characteristics to warrant placing them in the same genus. Photo by Wayne S. Leibel.

Biotodoma cupido
Figure 12: Biotodoma cupido, mature male (4 inch TL). Placed earlier in teh genus Mesops, Eigenmann and Kennedy (1903) erected the new genus Biotodoma for this fish upon discovery that the name Mesops was preoccupied by a genus of bettles. Photo by Wayne S. Leibel.

Gosse (1975), for example, in his monumental revision of the genus Geophagus, had opportunity to study updated material from many major museums throughout the world (the luxury of airplanes!). Over the years, preserved specimens of Geophagus jurupari or jurupari-like fish (Figs. 9 & 10) had been accumulating from diverse Amazonian, Guyanan, and Venezuelan collecting sites. Although Gosse found that specimens from these three localities differed slightly in proportion, meristics, and coloration, they represented, in fact, normal variation for such a cosmopolitan (i.e., widely-distributed) species. The "species" Geophagus pappaterra Heckel 1840, leucostictus Muller and Troschel 1848, macrolepsis Gunther 1862, and mapiritensis Fernandez- Yepez 1950, most of whose holotypes Gosse re-examined, fell within the extremes of variation noted in this larger modern pool of specimens that had been accumulated over the hundred-plus years since they were described, and thus they were all referable to jurupari Heckel 1840. Because of the chronological relationship of the names (all except pappaterra described more recently than jurupari) these became junior synonyms of the species jurupari Heckel 1840. Whereas Gosse (1975) points out that sub-specific status for the Amazonian, Guyanan, and Venezuelan forms is statistically warranted, he opts for the more conservative lumper's approach (vs. splitter) by synonymizing all with Heckel's (1840) jurupari.

Species are not the only taxa that are renamed, redescribed, or synonymized. Gosse (1975), in the same revision, separates a suite of four geophagine fish from the La Plata drainage (Argentina, Paraguay) from the genus Geophagus and re-erects a distinct genus, Gymnogeophagus, for them (Figs. 11 & 12). This splitting was first suggested by Ribeiro in 1918 who is responsible for the name, on the basis of only one shared trait (lack of cheek scale, hence nude = Gymno), and was therefore ignored by subsequent workers. Gosse x-rayed the various species in question and noted major differences from Geophagus proper in the attachment of the dorsal fin to the skeleton, which they all shared. This, along with' Ribeiro's scaleless cheek character were sufficient, in Gosse's opinion, to re-erect and adopt Ribeiro's (1918) genus. The history of another related genus, Biotodoma, illustrates change of another sort at the genus level. Biotodoma cupido, a geophagine-like cichlid (Fig. 13), was originally described by Heckel (1840) in the genus Geophagus. This fish was promptly removed by Gunther 1862 and a new genus, Mesops, erected for it and the related species, wavrini. Eigenmann and Kennedy (1903) pointed out that the name Mesops had already been used in 1820 for a genus of beetles, and thus was invalid. They replaced Mesops with the nomen Biotodoma on this basis, with Mesops sensu Gunther (1862) considered a junior homonym of its earlier beetle counterpart. Discovered homonymy is not at all rare, given the natural reluctance of ichthyologists to read insect (for example) taxonomy, and has happened more than once in the family Cichlidae alone.

Who's Right and Why Bother Anyway? Who's right?

Can Gosse be believed? Why bother applying scientific names if they are destined to be changed anyway? The first two questions have been admirably addressed by Jim Langhammer in a brief commentary that appeared in Buntbarsche Bulletin relative to a debated designation of identity. He writes: "as you read this article and all other articles dealing with the proper name of a fish, remember that you are only being exposed to an opinion except in rare cases where the actual taxonomic legality of the name is involved, as with junior synonyms or homonyms. You may choose to take sides but regardless of the preponderance of support in any one direction, no opinion is ever wrong, only more popular!" Gosse's (1975) conclusions regarding both the lumping of species into jurupari and the splitting of the genus Gymnogeophagus from Geophagus proper are one man's opinion, indeed, but the evidence he marshalls to support his conclusion is voluminous and meticulously presented and I am inclined to believe it.

What of the obvious fallout to the hobby? How can hobbyists keep up with these changes in nomenclature? Why even bother? The killifish hobby is the best testimony to why and how one should and does keep abreast of nomenclatural change. Firstly, the sheer numbers of killifish species known to science and available in the hobby mitigates against using common names: no precision would be possible. Secondly, the bulk of species acquisition goes on through the domestic and international mails with members buying, sight unseen, various species. It's one thing to select a fish whose appearance excites you directly from a dealer's tanks (I would concede, the precise name is relatively unimportant here if you like the fish), it's quite another to buy unseen from a list. Buyer, beware! However, killifish hobbyists are quite "nomenclaturally literate" and attuned to the problem: they deal comfortably, and most times accurately, with Latin, polysyllabic names. The organization does its best to keep members informed of name changes, and new species introductions by publishing accurately identified photos in their journal (JAKA). Additionally, the Killifish Master Index, brainchild of Christopher Carr in the mid-seventies and piloted to its current state of completion by Ken Lazara, presents a list of accepted species names and related synonyms, and is revised periodically by Lazara to accommodate nomenclatural changes; synonymizations or newly-described species. It is a mammoth job, and for his great service Ken Lazara was made a Fellow of the AKA. The same can be said for the American Cichlid Association, and I would imagine, the other specialty organizations. Buntbarsche Bulletin (ACA) is likewise a calculated mix of scientific and hobby-based information. Cichlidist's Library, a sporadic feature of the magazine, keeps members abreast of nomenclatural changes, and a slide series, now approaching 200 slides, of correctly identified cichlids that typically do not appear in established hobby compendia, is available to mernbers. In brief, the specialty organizations provide the best and most efficient way for the hobbyist to keep up with changes in nomenclature.

True, becoming comfortable with scientific nomenclature, may be initially difficult, and certainly name changes of the sort reviewed in this essay (e.g., the hondae, pellegrini, steindachneri situation I have elaborated throughout) cause added problems, but the advantages that accrue from the proper identification of fish, in general, far outweigh the trouble. Insofar as scientific nomenclature and accurate identification allow precise communication between hobbyists and other hobbyists, and between hobbyists and the scientific community, they are important. In the second part of this essay, I will present a strategy for accurately identifying the fish that you keep and, in so doing, hopefully, provoke some of you into making real and lasting contributions to the hobby. It's a challenging and exceedingly valuable enterprise.

Postscript to Part 1 The rules of nomenclature are complex and often difficult to understand. The reader is referred to Mayr (1969) for the complete text of the 1964 Revised Code and for a complete and excellent discussion of the science of describing and naming organisms. Simpson's (1961) Principles of Animal Taxonomy is also invaluable. More general, but nonetheless excellent, discussions of taxonomy and systematics are to be found in any number of college-level Introductory Biology texts. In particular, Wilson (et. al., 1973) Life On Earth (sinauer Assoc.) has an excellent chapter (24) that deals with taxonomy and phylogeny at a more basic level and leisurely pace than this article. I heartily recommend it. For a brief synopsis, Axelrod and Shultz' (1955, McGraw-Hill) Ichthyology Chapter, especially pages 4-8 in Handbook of Tropical Fishes is quite adequate.


  • Axelrod, H.R., et. al., 1980 Exotic Tropical Fishes, Expanded Edition TFH Publications, Neptune, N.J.
  • Goldstein, R.J., 1973. Cichlids of the World, TFH Publications, Neptune, N.J.
  • Gosse, J.P., 1975. Revision du genre Geophagus (Pisces: Cichlidae). Mem. Acad. Roy. Sci. Outre Mer (Bruxelles) 19(3): 1-172.
  • Gosse, J.P. and S. Kullander, 1981. The Zoological Name of the Red Hump Geophagus. Buntbarsche Bulletin 83: 12-17.
  • Hoedemann, J.J., 1975. Naturalist's Guide to Freshwater Aquarium Fish, Sterling Pub. Co., New York. Innes, W., 1938. Exotic Aquariwe Fishes, Innes Pub. Co., Phila.
  • Langhammer, , 1980. Technical Editor's Note. Buntbarsche Bulletin 81:21.
  • Loiselle, P.V. 1974. The Identity of the Red Hump Geophagus. Buntbarsche Bulletin 40: 9-19.
  • Mayr, , 1969. Principles of Systematic Zoology, McGraw Hill, N.Y. Scheel, , 1968. Rivulins, TFH Pub. Co., Neptune, N.J.
  • Sterba, , 1966. Freshwater Fishes of the World, Studio Vista, London.
  • Taphorn, D.C. and C.G. Lilyestrom, 1979. Occurrence of Geophagus steindachneri in the Maracaibo Basin of Venezuela. Buntbarsche Bulletin 73: 5-9.
  • Terceira, A.C. A R. Slocum, 1975. Preliminary Report of the Aphyosemion bivittatun Study Group. J.A.K.A. 8(5): 136-139.

Link to Second Part


Leibel, Wayne. (Oct 13, 1997). "Of Pickled Fish and Ichthyological Sleuthing: A Primer For the Advanced Aquarist.. Part I: The Whys and Wherefores of Scientific Nomenclature". Cichlid Room Companion. Retrieved on Apr 17, 2024, from: