Cavefish are native even to the states. They are found in dark caves, (thus their name) and their blindness is due to something like evolution. Since they are in the dark, they don't need to see. They despise high lighting in their aquarium, which a lot of tropical fish (save most tetras and many noctournal species, including catfish, loaches, knifefish, etc) will be miserable without.
They are a schooling fish, comfortable in very large groups, and they would rather not have to put up a fight against ANY fish, regardless of how tough they are. To put them with other tetras would not be a bad idea, since they do love low light. To put them with peaceful tropical fish is another idea, but probably not a very good one.
Forgive me for being redundant, but they like low light while most tropical fish (excluding nocturnal species) enjoy the light. This clash of needs is really quite simple to avoid by keeping low-light loving peaceful species together. Any kind of neon tetra--the classic, orange, or black--is an idea. They are all VERY beautiful fish that love low light.
These fish are used to cave floors that are filled with water in the wild. This means that perhaps there would be obtrusions in the wild, so their should be obtrusions in the tank. This can be achieved through driftwood (cured) and rocks. Plants are optional, since most plants will not thrive on low light and few plants occur in cave floors.
The blind cave fish requires a somewhat larger tank, although it is possible to keep them in smaller tanks. Recall that I said they would do best in a large school. This is the reasoning for the large tank.. Say, 30 gallons plus. Also, the obtrusions in the tank would take up a lot of space, so if you're planning for that, a neat tank to have would be a 55-75 gallon with a large school of cave fish and tetras. While a decorated aquarium looks nice, place decorations on either side of the tank or low in the middle to provide plenty of swimming room for the fish.
A bit of information on the fish:
(as taken from http://www.stlzoo.org/animals/aboutt...dcavetetra.htm
Dozens of fish species spend their lives in caves or underground springs, and most of them are blind. In this particular subspecies of Mexican cave fish, the animals' ability to see depends on where they live. Fish from populations that live entirely in isolated caves are totally blind. Those that lives in caves connected with a surface river have well-developed eyes.
Those that cannot see can still navigate easily through their environment. That's because cave fish have an extremely sensitive lateral line, the sense organ that detects vibrations and changes of pressure in the water. This sense allows the otherwise blind fish to detect obstacles and moving objects.
(taken from http://www.petresources.net/fish/cha...t_fas_mex.html
These fish are born with eyes, but skin grows over them as the fish develop.
(Even more information from http://www.timstropicals.com/Invento...ndCaveInfo.asp
The Blind Cave Tetra is also known as the Mexican Tetra, Blind Cave Fish or the Silvery Tetra. They are a good beginner’s fish, as they can tolerate great variation in water temperature and quality. The scientific name was originally Anoptichthys jordani, but it is now classified as Astyanax fasciatus mexicanus. The Blind Cave Tetra is a northern sub species and is found in cave waters in Texas and Mexico. The eyed version extends from Central to South America.
The body is a flesh/silvery color without features and the fins are colorless. The dorsal fin has a broad arch to it. The main feature of the Blind Cave Tetra is an absence of eyes. They are born with eyes, but the sight deteriorates quickly and the eyes become distorted and covered over within a few weeks. They navigate in darkness quite well and have well developed taste buds. This schooling fish has an ability to avoid bumping into other fish, which is not clearly understood.
Blind Cave Tetras should be provided with dim lighting and small to medium size gravel. Or, better yet, give them some caves. Plants are not essential. The tank should be covered as Blind Cave Tetras will jump when they are stressed. They eat flake foods, freeze dried bloodworms and live brine shrimp.
Blind Cave Tetras are one of the more aggressive tetras and they will nip fins. They should be kept with aggressive larger tetras, such as the Buenos Aires Tetra, the Colombian Tetra, the Serpae Tetra and the Silver Tip Tetra. They are definitely not good companions for smaller tetras and guppies.
The females are larger and broader, especially when laden with eggs. There is no distinguishing color difference between males and females. If differentiating the sexes is difficult, the best way to breed Blind Cave Tetras is to start with a group of about 6 and let them choose pairings. They are typical tetra egg layers. Parents should be separated and fed live foods prior to spawning. A drop in water temperature may induce breeding. Up to one hundred eggs can be scattered throughout the breeding tank. The parents should be removed after spawning. The eggs will hatch in a couple of days and the fry will be ready for brine shrimp and finely ground flake foods within a week.
Hope this helps some.
Blind cave tetras are wonderful fish, but they do require a bit of thought and are not suitable to be contained with just any tankmate, regardless of their peaceful disposition.