I have 2 large plecos(9-10") we just brought in yesterday from Koi pond. good thing due to temp dropped to 62 this morning! we have I think 40 gal rubbermaid black stock tank, with 2 aerators going, and a plant, and algae tabs. still have one 4 inch pleco and one 4 " algea eater in the pond to try catch, if it stops raining. we also have 10 gallon fish tank inside with 3three 1 inch algae eaters alone (growing them before adding to the pond). Q: need to get filter for the stock tank and large plecos? or just do water changes? and Q2: do you think it would be too crowded to put 1 smaller algae eater in fishtank with others and maybe the 1 small pleco? im afraid to put smaller ones in with the really big ones? theyre ok in pond together, but its a large koi pond with lots hiding spots. how do you tell if plecos are doing allright? we normally dont see them much LOL. they grew from 2 " from petco, to like 9" just from spring till now! tysm!