coconut shell has no value here; small piece of driftwood or cholla; floating plants (hornworth, pearlweed, frogbit, ...). For the first week or so the best option for the frys are live baby brine shrimp - the movement helps trigger 'eat me' reflex. After that fine food but use that turkey-blaster to suck out uneaten food. Putting them with the mom is fine but she is probably scared out of her wits so she has told the frys to hide.