sucker fish

Question
i have a sucker fish in a 20 gallon tank. i have the tank for almost 2 months now. i have guppy's ,molly's and tetra and neon in the tank? this morning the sucker fish is not as active and he is not sucking as much. is that normal? the sucker fish is also not moving as much? i clean the tank last night? he also have a places to hide?

Answer
Bernard,
To start, 20 gallons is not big enough for a Pleco. They can grow 18-24 inches and need lots of room. Depending on how many fish are in the 20 gallon, I am thinking it is over stocked. The molly is a brackish fish and needs to be in a tank with salt water. Remember, the Pleco eats the algae growing in the tank, but also needs to be fed. There are algae wafers and you can even feed him blanched veggies. Your Pleco will continue to grow even if he is in a tank too small and will die a premature death. Please, either get him the right size home,  gallon at least, or rehome him to someone that has the tank he can live in. I think he is reacting to crowed tank and as time goes on this will continue to happen.