Size of tank in gallons or litres.
How many fish and which type.
Waters stats in ammonia, nitrite, nitrate, and ph.
Any excess mucas on there bodies.
Check the gills over to see if there pale with excess slime, or red and inflamed.
Hi Hawkins…
Sounds very like what my Cardinal was suffering with…he had a colour change (loss of red colour, blackening of blue colour), heavy breathing, emaciated belly & hiding away at bottom of tank just floating etc, no interest in the rest of the group. (I've pics in my other post about it)
This had been going on 4 weeks!
So on advice of the guys here I gave the tank a dose of Interpet No.9 and he’s improving a lot. I’m hoping that he’ll make a full recovery….
Being really thin when still eating can mean old age, fish tb to internal parasites.
Check the fish anus to see if its enlarged or red and inflamed.
What does there waste look like when they go to the toilet.
Any worns prutruding from the anus.