you can try other things crushed as well..baby shrimp ...blood worms ..i use this stuff called fry bites i bought it at a local petstore for around 3$ ..my fry..(black ballon molly,white lyre tail, and black moore molly) are loving it! its very fine with extra nutrients..the cruched flake may not be small enough? i am not sure what are you housing them in and what is your water temp params?