A fishy friend from out of town showed up at the GSAS auction offering me a pair of livebearers that I had never seen nor heard about before. At first glance they appeared to be pupfishes, but he said they are goodeids, Characodon lateralis to be specific, possibly extinct in their native Mexican habitat. I immediately felt a responsibility to provide a tank so they could reproduce and the young be passed on to other willing aquarists. A five gal tank was all that was available so I set them up in that with some Java moss, sponge filter, and a table spoon of rock salt (and water of course!).
The 2 inch females are sort of an olive drab color with a few small, dark blotches along the lateral line. Males are full grown at 1 1/2 inches. Their lower anterior is light yellow which gives way to red across the posterior one half of the body below the lateral line. The unpaired fins are also red with a light black margin. Iridescent, almost blue scales cover the region from the caudal peduncle to the pectoral fins. Both sexes are stocky with an upturned mouth containing sharp teeth, thus the generic name Characodon (L.Wischnath,p.31) A feature that gives them a distinctive appearance is the extreme posterior placement of the dorsal fin near the tail. This would make them seem unbalanced in the water if it were not for the fullness of the body.
As livebearers I assumed that given a nutritous diet of flakes and adult live brine shrimp that soon there would be many fry released by the plump female. Day after day I would approach the tank expecting to see babies only to be disappointed. A month went by and the female was huge, she must be about to deliver over a hundred tiny fry. I began to worry that she must be having some problem because she just continued to eat like a pig and swell up. Finally after almost a two month wait I noticed the female looked like a nearly deflated inner tube. Searching the tank I found nine absolutely huge babies. I was shocked at their size. They feasted on baby brine shrimp and took flakes immediately. Growth was rapid and the males began to show color at about 1/2 inch. Lothar Wischanth states in his definitive book, Livebearers of the World, that C. lateralis is disease prone in the aquarium but I have not experienced that. He also says that algae are the main diet in the wild so it is wise to include live plants and some algae in their tank. They probably would benefit from inclusion of spirulina flakes in their diet as well.
If you are looking for something a little different that is not likely to be found in a shop, I recommend this cute little goodeid.
Reference: Lothar Wischnath, Livebearers of the World, TFH 1993, pg. 31-32