Will 1 Otocinclus Vestitus control the algae growth of a 5 gallon or will I need more to do that? Also, will 4 Otocinclus Vestitus control the algae growth of a 10 gallon or will I need more to do that? I would appreciate the help!
1 is enough, but they are schooling fish, keep that in mind. And you should really have a few and a small tank won't be able to handle bioload and lack of algae.