I love otocinclus cats. I have a bunch in my tank. I've had both regular otocinclus, and niger otocinclus cats. My LFS also has zebra otocinclus cats, but at $8.99, I'm going to wait until my tank gets older (3 months). I also just got a farlowella catfish. He's really cool looking (twig shaped), and also eats a lot of algae. I wouldn't recommend him for a small tank though.