I have a 300 gallon with a 12 inch porcupine. I had a 5 inch mappa and a 5 inch stars and stripes. The porky was initially fine with them however after about two months became very agressive and began chasing them around the aqarium. I eventually pulled the Mappa and the Stars and stripes out and are currently together in an aquarium by themselves. So to answer your question it really depends on the puffers personality. If you do add them together make sure you have a large tank, plenty of live rock and be prepared to remove one if necessary. Good luck!