Yes to pleco. They dont clean up waste but they stop algae growth. I would say that the jaguar with the green terror would work as long as they are introduced around 3 inches but no guarantees cuz some jags cant stand tank mates and some will take their territory and hold it. I think with a tank that big the jaguar will probably just take a part of the tank and let the others have the rest. I like the catfish idea. I think 4 or five pictus cats would really make the tank active cuz they never stop moving. I had them with my jaguar and he didnt seem to mind and i really liked how much energy they gave to the tank.