The Lost Treasure of the Aztecs
By James K. Langhammer
1999 revision of 1976 article that appeared in the Spring 1981 American Currents
(This is an article originally written in 1976 and published in TROPIC TANK TALK of the Greater Detroit Aquarium Society and in LIVEBEARERS of
ALA. It was revised in 1982, and again in 1999. It is the first part of
a series by the same title. The author gave NANFA permission to reprint it)
History books tell us that in the early 1500s the Spanish Conquistadors destroyed, as a
political entity at least, the great nation of the Aztecs in the central highlands of
Mexico. In their relentless search for gold and other treasures, the Spaniards pillaged
the American cultures until one by one most of them fell beneath Spanish domination. Yet
history also alludes to the fact that the New World's ultimate treasures as envisioned by
the Spaniards were never found. Why? Where were they hidden - and by whom?
Perhaps, the real treasures of the Aztec empire were hidden to the
Europeans by their own inconsummate greed, and have continued so to this day! Gold and
gem-stone ornaments were probably more beautiful than valuable to the Aztec people whose
artifacts reflect the great majesty of the natural world around them.
Part of the beautiful baubles of the everyday world of the Aztecs still
shimmer in the hot sun of the Tropic of Cancer, vicariously reflecting the Sun-god's
radiance off their animate flanks in a brilliant blend of opalescence and pigmentation,
and STILL are unknown and unappreciated by the modern world! - the Goodeids, a fascinating
family of livebearing fishes.
The family Goodeidae is restricted to the ancient Aztec domain of
west-central Mexico. Using the state capitals of Durango, Colima, Morelia, Mexico City,
Queretaro, and San Luis Potosi as boundary references, the total range of the family which
consists of approximately 36 species in 17 genera can be roughly circumscribed.
Goodeids are wonderfully interesting fishes, I don't believe any amount of paraphrasing on
my part could improve on what John Michael Fitzsimons (1972) says about the family:
||"The Goodeidae comprises a wholly Mexican family of viviparous
freshwater fishes represented by 35 or more species largely restricted to the highlands of
Mesa Central. Its focus of abundance is in the Rio Lerma basin where it is the dominant
family of fishes (Miller and Fitzsimons, 1971 ).
are generally small; members of two genera, Alloophorus Hubbs and Turner and
Goodea Jordan, attain a length of 200 mm, but most grow no larger than 100 mm.
They live in a variety of habitats, ranging from deep spring-fed pools to shallow riffles.
Some are lake dwellers: others abound in irrigation ditches that may have only a few
inches of water. Their body form often reflects habitat type. Certain river and stream
species, such as the Ilyodon Eigenmann, are swift swimmers with slim, streamlined
bodies and large caudal fins. In ponds, lakes, or quiet stream pools, deep-bodied forms,
such as Skiffia Meek, are slow moving and maneuver easily in dense vegetation,
sculling with the pectoral fins in a manner reminiscent of many resident coral-reef
fishes. Members of the genus Allodontichthys Hubbs and Turner look and behave like North
American darters (Etheostomatinae), are long-bodied bottom dwellers, and are found only
among the rocks and boulders in shallow riffles. Goodeids include all consumer types:
carnivores with conic teeth and a short gut, Alloophorus; herbivores with generalized
bifid teeth and a long coiled gut, Ameca Miller and Fitzsimons; or omnivores with
variable teeth and gut form, Xenotoca Hubbs and Turner, the feeding habits of
which range from nearly completely carnivorous to completely herbivorous at different
"The unifying features of the
family are related to mode of reproduction - internal fertilization and live birth. The
distinctive modification of the male anal fin, presence of an internal muscular organ of
apparent reproductive function in the male, structure of the ovary, and the development of
trophotaenia in embryos distinguish the Goodeidae from all other cyprinodontoid fishes.
The first six or seven rays of the male anal fin are crowded, shortened, and often
separated from the rest of the fin by a distinct notch; they probably aid in insemination.
The anterior anal rays of the male have been described as a "gonopodium"
(Turner, Mendoza, and Reiter, 1962), a term first applied to the elongate male anal fin of
the poeciliids, but this term may be a misnomer for goodeids since the role of the anal
fin in sperm intromission has not been demonstrated (Miller and Fitzsimons, 1971). Goodeid
males also have a short, highly muscular tube connecting the sperm ducts to the genital
opening; this structure has been termed a "pseudophallus" (Mohsen, 1961, 1965).
It is said to expel semen forcibly or to become everted and applied to or placed into the
female's genital opening, but, as with the "gonopodium", its function has only
been surmised and not demonstrated. Females have a single median ovary formed from the
union of lateral organ rudiments, the fused internal walls of which form the median
septum. Yolk is resorbed early in embryogeny and its nutritive function is assumed by
placenta-like trophotaeniae, rosette or ribbon-like growths which extend from the anal
region of developing embryos in all but one species (Turner, 1933, 1937)" - end
of Fitzsimons quote.
Since 1972 when Fitzsimons wrote the above, one major systematic
change affecting his words was Parenti's 1981 revision of the family Goodeidae to include
two egg-laying genera within a new subgenus Empetrichthyinae. Currently I believe
all taxonomists accept Parenti's conclusion that the egg-laying genera Empetrichthys
and Crenichthys are indeed similar to what primitive goodeids must have been like
and that by including them into the family its range is now extended north of Mexico's
My primary purpose in writing this account is to introduce to aquarists
several species of the live-bearing goodeids and my impression as to their value as
The first species I'd like to mention is my unquestioned favorite - the
Rainbow Goodeid, Characodon lateralis. I know of few fish with more color in wild
stock than the Rainbow Goodeid; with judicious selection I believe this species can afford
aquarists with at least as many colorful strains as have the platies and swordtails. Males
are primarily red with yellow, green, black, and brown markings. It is true of all
goodeids and many fishes generally that body pigmentation may be enhanced by iridescence
reflected from light sources back to the viewer - resulting in visual splendor not seen if
the fish are viewed in poorly lighted situations. Rainbows are peaceful with other fishes
-although as with all goodeids some fin-nipping of other fishes seems to occur if the
goodeids are not regularly fed well. Generally goodeids do not cannibalize their own young
unless the parents are inadequately fed and maintained; thus multiple generations are
easily exhibited together. Goodeid species should be housed separately, however, since
some interspecific hybridization has been documented (Fitzsimons, 1972).
Rainbows can grow to 60 mm total length. Like all goodeids, they are
not fussy eaters; although morphological details indicate many goodeids are adapted to
herbivorous diets, my experience has been that they all relish and even prefer living
The Rainbows are the most northern known viviparous goodeid and occur in springfed streams
near Durango. Perhaps, their occurrence in the clean artesian waters explains their
extreme inability to tolerate "old" water - they MUST have frequent water
changes to offset the acidifying, polluting effect of metabolic wastes. In my Detroit
water with pH of about 7.2 and 120 ppm of carbonate, a downward shift in pH can quickly
become fatal to goodeids. I imagine hard, alkaline waters are much more to their
My partiality to the Rainbow fortunately, doesn't diminish my opinion
that the best of all aquarium goodeids is the Butterfly Goodeid, Ameca splendens.
Like a giant Nothobranchius, the Butterfly's beautiful colors and frenetic
activity will endear it to most hobbyists. The female Butterfly is basically a black and
brown variegated version of the male, which displays true elegance. The males have
iridescent green flanks which are flashed like a spinning prism as the fish darts around
the aquarium. The caudal fin is widespread at all times, providing magnificent contrast
between the broad black submarginal band and its wide border of canary yellow.
Butterfly Goodeids are large fish growing to 100 mm, with some of the
largest newborn babies I've seen among bony fishes - 20 to 24 mm at birth! They are
peaceful and seem more tolerant of old water than most goodeids are.
The Blue-tailed Goodeid, Ataeniobius toweri, has little to
recommend it in my opinion. It is a slender fish growing to 100 mm. On the flanks are two
parallel, horizontal stripes and in the male the caudal fin is a beautiful pastel blue by
reflected light. The Blue-tailed Goodeid is sensitive to water quality. It is the most
easterly of all goodeids and it alone lacks the well- developed trophotaeniae so
characteristic of goodeids; for that reason it was once considered the most primitive
member of the family. Recent research suggests instead that the trophotaeniae were lost as
Ataeniobius evolved from the genus Goodea. It is one of the few species
in which I cannot see sexual dimorphism at birth; visible anal-fin modification in males
seems to occur at about 30 mm.
The Green Goodeid, Xenoophorus captivus, is another
that will never be popular. It was my first goodeid and I have maintained stock for over
thirty years and freely distributed the fish, but I know of few other hobby stocks at
present. This is too bad because it is a desert species and due to local irrigation uses,
its spring habitats are rapidly being destroyed. It simply will not tolerate old acidic
water and dies quickly if neglected. The males have iridescent green bodies and a rather
unremarkable cream border on the otherwise transparent caudal fin. One population from
Jesus Maria has better color over all and was only introduced into the hobby in 1998. The
species seems to be large at 60 mm.
A colorful species is the Picotee Goodeid, which has a scientific name
that is truly longer than its 40 mm adult size - Zoogoneticus quitzeoensis. This
is an elegant species, very much like the Merry Widow, Phallichthys amates
(Poeciliidae), in body shape and pattern. The dorsal and anal fins of males are picoted
(or bordered) in orange which can be deepened to blood-red if enough carotenoids are fed
to the fish; the caudal is colorless. The body of both sexes is boldly marked by large
blotches. Behavior is spritely but peaceful. A more recent introduction and equally
handsome is the Crescent Goodeid - Zoogoneticus tequila. It is slightly more
robust but differs in fin coloration - its dorsal and anal fins are bordered by creamy
bands and it is the caudal fin which is bordered by red-orange!
Just as the Mozambique mouthbrooder gave all Tilapia (sensu lato) a
"black eye" or undesirable status for most aquarists , so also I'm afraid the
Red-tailed Goodeid, formerly Xenotoca eiseni (now placed into the genus Xenotichthys
by Webb 1998) has adversely affected the attitude of aquarists towards the other Goodeids.
The Red-tail is a pugnacious, astonishingly fecund, hardy, and robust species which grows
to 80 mm. and seems to quickly wear out it's welcome for most aquarists. Please, however,
keep in mind that this fish is a rogue species and not at all typical of the family.
By contrast, the beautiful Jeweled Goodeid, Xenotoca variata,
is highly desirable although I am afraid it is destined to be overshadowed by the very
similar Butterfly Goodeid, Ameca splendens. The male Jeweled Goodeid has a
"crazy quilt" effect of opalescence on its sides - pinks, greens, blues - which
can only be appreciated by light reflected to the viewer. The creamy yellow tail border
loses effect by not having a contrasting submarginal band. Like the Red-tail, it grows to
80 mm. but seems to be a much gentler and acceptable community fish.
With these not-so-brief and yet extremely superficial comments, I hope
I have given you some insight to a relatively ignored and fascinating family of
livebearers. For additional reading I refer you to the bibliography below.
1. Fitzsimons, J. M. 1972. A revision of two genera of Goodeid fishes
from the Mexican plateau. Copeia 1972 (4):728-756
2. Hubbs C. L. and C. L. Turner. 1939. Studies of the fishes of the
order Cyprinodontes. XVI. A revision of the Goodeidae. Miscellaneous Publications No. 42,
Museum of Zoology, University of Michigan: pp. 1-80.
3. Miller, R. R. and J. M. Fitzsimons. 1971. Ameca splendens, a new
genus and species of Goodeid fish from western Mexico, with remarks on the classification
of the Goodeidae. Copeia 1971 (1): pp. 1-13
4. Norton, J. N. 1981. Goodeids - Mexican livebearers. FAMA: October and November, 1981.
5. Parenti, L. R.. 1981. Phylogenetic and biogeographic analysis of Cyprinodontiform
fishes (Teleostei, Atherinomorpha). Bulletin of the American Museum of Natural History,
Vol. 168: Article 4, pp. 1-557.
6. Turner, C. L. 1946. A contribution to the taxonomy and zoogeography of the Goodeid
fishes. Occasional Papers of the Museum of Zoology No. 495, University of Michigan. pp.
7. Webb, S. A. 1998. A phylogenetic analysis of the Goodeidae. Unpublished Ph.D. thesis,
Univ. of Michigan.
Used with permission. Article copyright retained by author.