I housed a fellow hobbyist fish in three aquariums. My Quarantine Tank, Ione I rapidly set up and my Frag Tank. Clowns and a Yellow Chromis went in the Frag with an Anemone. He got his fish back last Sunday and is now blaming me for Brook. I haven’t seen any signs of Brook. I’m very careful about cross using implements, without cleaning and soaking. How do I tell if I have Brook, in the Frag Tank? Treatment. BTW, I have live rock in this Frag Tank.