I have a group of about 50 cards in my planted 240 gal. with discus. I find they are not fussy at all. They eat what the discus eat, which is beef heart, bloodworms, brine shrimp, daphnia, blackworms, glassworms etc. They have never tasted dry processed food. They thrive in there at 84 degrees. IMO, they do better at temps. around 82 to 86, although depending on other factors, one may not want to keep it quite that high.