What's Shaped Like A Pear And Has 2 Genomes? Check The Pond for Tetrahymena thermophila.
If you could peer microscopically into the closest freshwater pond, you'd hesitate before dipping a toe. Amid the murky water, you'd probably notice an oddly furry, pear-shaped organism gliding along--and gobbling up everything in its path.

The rest of the story for anyone interested:

http://www.sciencedaily.com/releases/2006/08/060828211914.htm

If you could check out your saliva microscopically, you may never want to kiss anyone again.

If you checked the dust coming out of your bed mattress you'd start sleeping on a stainless steel bed.

Can they be feed trained?

Tetrahymena has built an eating machine that allows it to digest nearly any protein it encounters.

These things can be used to clean up any protein. You could tune them to specific pond problems and market them. We could go into the TT supply business.