I have a
clarkii clown in my
quarantine tank along with a coral beauty and a falco hawkfish. (They are in time out because they have been naughty.

) They are there for about a month until I finish adding fish because they have been terrorizing any new tankmates. All of a sudden the clarkii is having troubles going to the bottom of the tank. He bobs along the top, trying to dive. He is still eating and appears healthy apart from the fact that he is slightly lighter in colour than normal. Any ideas as to what is causing this?
Thanks,
Ghoti