(I initially named him Perky the Plec before I discovered the truth-I kept the name afterwards though.)
Its a tank cleaner, though it doesnt eat the algae but rather the tiny creatures that live on it (aufwuchs)
I've had this fellow over a year now and he hardly seems any bigger so I presume they are a small species. They need a fairly high O2 content so a good stream of air bubbles is a must, tho I turn the pump off at night and it suffers no ill effect for it.
More info on them here:
http://www.loaches.com/articles/hillstr ... -fast-lane