For about two weeks now my sisters Synodontis Decorus has just been sitting nose to the surface tail to the bottom and has been a distinctly dark colour. Anyone have any ideas. Has been treated for internal bacteria.
Okies, usual stuff first. Have you checked the water parameters for Ammonia, Nitrite and Nitrate? Always a good starting point.
Assuming they are all ok what about the water temp? In this warmer weather the tank temps often riseand that can lead to an oxygen depletion in the water. Is he/she breathing quite heavily? (Gills going rapidly) I have a Decorus and he's never acted like that. Only time he tends to be out is well after lights out or, when I first had him, he stayed near the front glass just because he was so stressed by his new surroundings. They are a particularly sensetive syno and hate change of any kind. I know he's comfy now as he has a large place to hide and still be able to see what's going on. Always has his eye showing through the gap.
Anyways. Check all the things, add more oxygen to the water and look for any other possible signs of trouble. Pretty much all you can do.
P.
Water params and temp are fine. Breathing normal (in fact sometimes you have to look real close to see if the fish is actually breathing at all). I suggested an airstone which they added but hasn't made any diff.