Had an interesting experience with the arrowhead. I had a bit larger growout cichlid I needed to cull (healthy, but deformed) Threw it into the tank expecting carnage but the puffer sized it up and left it alone. Made me think that I might be able to keep a tank mate with this guy IF I kept it in the 65B and it was the right size/temperament. With the algae growth in this tank I have a large bristle nosed pleco I have in mind. Also something like a large angel fish might work. Total experiment that could end in disappointment and disaster but considering it....