You might be surprised at how much live food they do eat. But if the food is of freshwater origin it will live in the tank until it gets eaten, so Daphnia, bloodworms, Tubifex, mosquito larvae etc will be OK. Brine shrimps are good food, but as they live in salt water, they won't survive long in the tank, so you shouldn't feed too many of those in one go.
You can also culture your own live foods. Daphnia don't need much work if you only need small amounts, and whiteworms are quite easy.
Microworms will be useful for the babies if your Apistos start breeding.
