The tetra species is omnivorous in nature, and will eat most of the types of food, including flake food. You can feed your tetra with freeze-dried bloodworms, tubifex, brine shrimp, daphnia, etc. As for the fry, i.e., the young fish, they should only be given tiny bits of food because of their small size; newly hatched brine shrimp would be an apt choice.