Blind cave tetras are very nice fish. But they can annoy other fish, either through their endless swimming or by their frenetic feeding behaviour. So I wouldn't mix with anything delicate or nervous. Cichlids tend to be annoyed by them, I think because the tetras swim through their territories, unable to see the cichlids to take notice of them. Given they like (need) hard, alkaline water, the ideal tankmates would be things like swordtails or mosquitofish. They do NOT like soft/acid water, and nor do they like high temperatures, so keep the heater at 25C or less.
A nice tank for them is one designed for low-light fishes. Use black sand, lots of vertically arranged slate to create "stalactites", and then just one small light, maybe a reddish grow-lux type thing. This sort of tank looks very eerie, but the tetras fit right in. Catfish will do great, too, and the more light-phobic species like doradiid and small Synodontis catfish might actually swim about a bit.
Cheers, Neale