hey guys. i have a green spotted puffer in a 45gal brackish tank. Hes about 3.5" and i was wondering if i could add another gsp around the same size. Would they get on ok. cheers

I'm afraid in the tank you have one is enough. I think you need a 65 gallon for two. Any tank mates are a risk. It seems to partly depend on personality. As they get older they tend to get more agressive too.

I know a HUGE tank with a large group of gsp and archer fish that seems to work well. Monos and scats can also work but again need a big tank. Some people have tried mollies but they can bully the GSP or they might end up dead one day. Others keep them in full marine water and have a few more choices. It's always a bit risky though and your tank isn't really big enough for most possible tank mates.

For more info try here:The Puffer Forum • The PufferPedia

i agree with what snail replied.it may seem like a waste of water but they seem to prefer that lone wolf thing,and a plus is you can get to know your puff a little more intimately they are like little puppies