Malaysian Trumpet Snails
These snails are little conical shaped things. In my local fish
store, they're in almost every tank. They burrow deep into the substrate
and keep it from getting compacted (too much). They only seem to come to
the surface when the nitrate levels are really bad so they can indicate a
tank that needs a water change. I just started adding them after reading
some posts about their benefits. I've been having trouble establishing a
good colony of these guys because my clown loach seems to think these are
just snacks for him. When I first started keeping aquariums, I'd always
have a bunch (didn't understand the concept of water changes). If you
really want them and can't find them, mail me, and I'll send them as the
store gets more.
P.S. I think they reproduce asexually so it shouldn't take many to seed a
tank as long as you don't have a clown loach with a voracious appetite. The
clown loach is the reason I can't keep glass shrimp either.