[waterfaller1]

That may be true in a larger tank. Personally I wouldn't try it in a nano. Nowhere for that other fish to go if he is being tormented. Shrimp are alot of fun, just give the tank some time to mature before adding them if you decide to. You might get away with two puffers, but they would have to be monitored closely. The tank should be set up with lots of plants and hardscape to break up the line of sight.