mine dont nibble though lol, they pick the whole thing up, and it looks like if its jammed in thier mouth, then they jus keep like sucking out it till they get it in lol
That's what mine do! No harm done, they just suck bits off. Stops them gulping it in one.
would these do any good?
http

/www.ebay.co.uk/itm/BLOODWORM-PELLET-Apple-Snails-Catfish-Loach-Plec-/350130467262?pt=UK_Pet_Supplies_Fish&hash=item518566f1be
Maybe as a treat food. Like I said, you're after an all round food.
Try the jbl novo tabs. Seem expensive, but I bought a tiny pot and its lasting forever. One feeds my whole tank so they go a long way. You can even stick them on the inside of the tank for smaller fish to graze on.