they are mid-level catfish. They are cool, and I don't think they will eat algae, but Plecos, what everyone calls algae eaters are armored catfish and they love algae. They get huge though. There are small species, but they can be expensive, and may not eat algae at all. Just depends on the species. I've read that mekong catfish eat algae, and they grow to more than 9' and wiegh more than 600 lbs. Again just remember there are more than 2750 different species of catfish named right now, and they are currently trying to fill in all the gaps to the estimated 3500-4000 species that is believed to exist.