I have a "little" tank - think only 2.5 gallons - it's a desk top Fluval - I have one little puffer in there and want to add more - is the tank too small to have say "3" of these little guys? I think they get to 1 inch.
Do you mean Dwarf puffers, if so they require 5gal per puffer, some say 5g for the first and 3g for each additional one. So your probably best keeping just the 1