I have lost 3 so far. I have treated with OTC antibiotics and antifungal meds. Also treated one round with an an anti - parasite med. Symptoms are not eating, listless fish, hanging at top, some display a moderately thicker slime coat and those I lost had no slime coat and looked like slight puffiness in the skin between scales. It started with some dimes I had shipped to me and then spread to one other tank. It seems to be mostly effecting my blue angels. I have been researching and have found that Chilodonella is a possibility (it is the closest thing I have found searching symptoms ). I have added a salt treatment and so far so good. Nobody seems adversely effected by it so far. Watching close though. Any experience or advice is welcome please.
If they are hanging at the surface it is possible that parameters may be off, gill damage or even parasites.
Are the fins affected? Thickening of the slime coat is most often parasitic and some often affect the fins.
You mentioned this started with new fish. Have you checked with them? Were these fish imports?
Do you have any photos? Might make it easier, and someone may pick up on something that has been overlooked.
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