Ugh bad morning

[MarkoD]

walked by the tank while the moonlights were on this morning and i see my moorish idol all beat up and missing a bunch of his fins.

looks like he got beat up.

the most recent fish i added was the black shoulder tang and for 2 weeks now he seemed to fit in just fine. no aggression towards anything.

i moved the idol to my refugium but i dont know if its gonna make it

anyone know why fish suddenly snap and become aggressive?