We add a copperband 8 months ago in the 265g reef because of aiptasia invasion. It ate all the aiptasias (and feather dusters, but it was not a problem because it was more invading then being cool).
We have 4 clams (2 crocea (small) and 2 squasmosa (1 medium and one monster) and the copperband never nip at them... neither at the corals...
It eats mysis and nips at krill piece (the krill of the triger and tangs,
)
It will come eat in my fingers and snaps mysis all around.
