Adding a clown

[cd5]

If I have an established clown in a 20 gallon and want to add another(identical) one, should I add a larger one or a smaller one, any other advice about adding another, I don't want to stress out my current fish or the new

 

[Jason]

my maroon and gold banded clown tried to kill a smaller almost as soon as I put the bag in the water to begin acclimating him (yes, the bag was still closed)

unless they are percs I wouldn't even try it. and a bigger one would probably work out better I would think