How many dwarf puffers will I be able to add in my 20 gallon tank?

I want to add 3 dwarf puffers to my 20 gallon tank. I have 2 yoyo laoches, 2 guppies, 3 platties, 1 bolivion ram, and 17 guppy + platy fry (will give all my fry away), In my 20 gallon tank. Do u think I can add three dwarf puffers to my tank