Larvatus Butterfly not eating

[EmilyB]

My Black Back is probably one of the hardiest fish I own. Funny to see the rating on there..

Try to keep food small, chop up the mysis, or crush the flake. Is there a fish in there that is a good eater? Feed what it likes, but make it small. BFlys may also take to spirulina nibblers as if flakes off gradually into the water column.