I have had three African Dwarf frogs for almost a week. I've been feeding them fish flakes with a baster and at first my frogs really liked them, but now they aren't eating the fish flakes anymore. I have also tried pellets and sun-dried baby shrimp, but nothing seems to be working. I don't have any substrate so I leave some of the sunken fish flakes on the bottom. Could they be eating those when i'm not watching? Should I try something else? Maybe live brine shrimp? Thanks!