He is a model citizen... The Coral Banded Butterfly is know to be reef safe with Catiuon... My LFS has 2 Huge Coral Displays 600 Gallon +, with 2 very old full grown CBB in them.. They actually trust them...
If mine ever gives me a reason to not trust, I'll go from there...
Mine also ate from day one.. He eats like a pig. I made sure he ate in the LFS before I took him... I feed him BloodWorms and Mysis shrip soaked in Xtreme Garlic....