I want to upgrade my tropical 10 gallon tank to a 20 gallon?

Okay. 3 or 4 Otos are way too many for a 20 gallon tank. They scavenge for scraps and algae and a 20 gallon tank could not sustain them all. Angelfish are okay... Maybe consider some more tetra? (6 or more) Make sure you cycle your 20 gallon tank... Six tetras, one oto, one betta, and one angelfish would definetaly work.