Unkown Red Tail Shark Illness

[ltb11uk]

My red tail shark keeps resting and just lying there. He is suffering from ich at the moment. Well he was im unsure if he is now. I cant see any white spots anymore.

What is wrong with him?

 

[WILDER]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

It could be a number of things so need to rule out bad water quality.
What med did you use and how long?