http://www.thekrib.com/Fish/Algae-Eaters/
The illustrations are line drawings. Sometimes drawing are more help than actual photographs, other times they are not so helpful.
If that article doesn't help you ID your fish, highlight and copy the scientic names of those critters, paste them into a Google image search. That should do the trick.
By the way, what ever that algae eater is, it shouldn't be changing its attitude quite that quickly. (Oh blast! Here it comes again!) Have you considered a partial water change. ;)
Good luck on the ID. Ah and you could always call the shop which sold you that fish. They should have a wholesaler's invoice listing it. (Not that whole-sale places are always correct.)
ATB!
unc