I got my small blond naso about two months ago from a reputable quarantine facility. He has been eating spirulina brine and seaweed regularly. I woke up today and he has been hiding in a cave. He's displaying his defensive spots on his body and can't seem to keep his balance upright. His tank mates are all peaceful towards him. He is leaning on his side constantly and will only accept very little food. Normally he's a pig. All other fish in my tank are happy and healthy. Did all my normal water chemistry test today and everything checks out. How can I save this guy? Does anyone have any expertise in this area as to what these circumstances mean as far as a diagnosis. This really breaks my heart