I have 5 Astyanyx Jordani in a 29. They were originally the first fish in the tank after an overhaul because they were cheap and i didn't have a light yet, but they are some of the coolest fish i've kept. Really neat fish but tough to keep with tankmates. First I tried Barilius danios, which lasted about a week. I later found that at night the tetras would gang up on them and devour them alive when it got dark and they got stressed. After this i got some D. Compressiceps growouts a few months later, which worked out decently. they'd fight back so the Astyanyx quickly learned to keep their distance. I now have the tetras with a single exochochromis anagenys growout. the big issue with tankmates is feeding them. when alone they'd have little issue feeding, as they'd swarm the surface once the food hit then scrounge the bottom much like cories. But when i have them with other fish they always miss most of the food, making it difficult to ensure they get enough. they definetely lost weight until the comps were put in my 75. But they learned a good trick with the exo, who usually gets 99% of the food. The exo doesn't really swallow then move on. He just crams as much as he can into his mouth, then waits for it to begin disintingrate before crushing it. once there is nothing left in the water they just follow the exo. when he crushes the pellets about half ends up as suspended particles which the tetreas eat right up, coupled with hand feeding ensures they don't waste away.
