Welcome to the forum! Your tank looks good, but angelfish should be kept in 29 gallon tanks at the minimum IMO. Rummynose tetras really need more room to swim too. Most people say that rummynoses need 30 inches of length (ex: 20 gallon long). Usually people say that ottos need to be kept in 10 gallons at the minimum. If I were you, I would re-home the current fish and get some nano-fish like chili rasboras.