Flakes, sinking pellets, frozen foods (bloodworms, bbs, etc.)...basically whatever they can get at. I've seen them nibble at some veggies too when it gets softer but I have no idea how effective their mouths are at getting a hold of such large chunks. I would usually alternate sinking pellets about every other day to make sure they were actually getting some food themselves since the danios that were with them gobbled up most everything before they even noticed there was food in the tank (they are the most oblivious fish, I swear). I usually dropped one in a little before the lights went off.