bumble bee catfish
I have had a bumble bee catfish for about 3 years now. They are very interesting. As long as you have a good place for them to hide they will get along just fine in your tank. Mine was never aggressive towards others and would only come out every once in a while and when he did he would swim at light speed.
I am actually looking into getting an albino catfish (the pl*co variety), although I don't know if he would get along with my royal pl*co in my 55 gal.