For starters Otos, like most Dwarf catfish, prefer groups of 3+. Otos CAN live alone but they won't be happy and can die of loneliness.
Also Otos should have tanks of about 20+ gallons, they have voracious appetites and smaller tanks can't support their dietary or community needs. Some places say they can live alon in 5 gallons but I'll emphasize the difference between CAN and SHOULD. For example I CAN live in a small closet and only eat a slice of bread and drink a glass of water a day but I won't be happy or healthy or live very long.
As for food you can try boiled organic spinach,lettuce,carrot,cucumber. You can also try breaking up the wafer and putting different pieces in different places so the betta can't find them all. Some otos are nocturnal so you can try feeding at night when the lights go out.
Edit: OFL Beat me to it.
Last edited by Malvolti; 03-08-2011 at 04:39 PM.