unfortunately you have some rather big fish already mixed in there.
Clown loaches - these guys can get around 4" long and like to be kept together in groups
Red tailed sharks - again, 4" may be aggresive towards other fish - I've never dealt with them to be honest
Pleco - depending on the type of pleco it could be anything from 3" to over 1ft long when it's fully grown! what type of pleco is it?
Also, Cory cats like to be in groups bigger than you have.
How long have you had your tank setup? is it cycled? do you know your water paremeters? (pH, nitrite, ammonia, nitrate etc)