i dont think id go with loaches cause you have big fish-eating fish and you already know what would happen to them.puffers are retarded too,the one i had would only eat blood worms and nothing else.the bottle method seems most likely to work,saying as veggis like to float.sorry that i couldent be much help.
i actually want snails in my tank but my oscar keeps eating them,even my big apple snail,no snail is safe with an oscar around.one time one of my oscars ate a crawdad and sh*t out all the parts in big chunks.i didnt know where they came from until i came to the conclusion that since he was the biggest fish in the tank (5-6 inches) by far,only he could have done it,talk about some major constipation.