Definitely a cycled tank and food source. My Ottos have been doing well after about 2 months. They love cleaning the live plants and glass on the sides of the tank. I supplement with algae wafers that they like also. The wafers are also a source of food for my Pleco and Rabauti Corys.
2 Angels, 2 Rabauti Cory, 2 Aeneus Cory
7 Neon Tetras, 7 Glowlight Tetra
2 Glass Cats, 2 Ottos
1 Spotted Raphael Catfish
1 Common Pleco