The reason why everyone is telling you to rehome your clown loaches is because of how large they will grow. These fish will grow up to 12" EACH. The advice you are being given is to keep your fish happy and healthy years from now. Is your tank large enough (atleast 18" in width) to allow this fish to turn around? That is why people are telling you to re-home these fish.
When you have the fish in a too small tank, they can become stunted. Even though they remain small, they are more prone to disease and live shorter lives. There is also on theory out there (no one can agree on this) saying a stunted fish's organs will grow to full size, but be crammed into their small bodies. Think about craming all your organs into a 5 year old's body. Sound fun?
Filtration will help deal wiht the waste producted, but not adress the physical space issue. Also, an over stocked tank needs more frequent water changes because the nitrAtes build up alot faster.
