What Should I Add?

I am buying a Green Terror soon and I think I will add some kind of bottom feeder to the tank with him. The room where the tank will be kept only has one small window so I don't think there will be very much alge for a pleco. I was wondering what kind of bottom feeder I could put in the tank. Will a few pictus cats be ok? What do you think is the best choice?

I don't have my tank yet, but I think it will be either a 33 gallon (36x12x18). I have been told a pictus cat or a clown loach might work.