Ol' Puffy.

[JayBMF]

I have a GSP that is about... 2.5" maybe 3", and I was thinking of getting another GSP. My question is; Will they get along? I'd hate for my larger one to pick on the smaller one. I have read several different outcomes. I suppose it depends on the fish itself, but it gets along with two other fish (Blue Gourami, grown goldfish). It's a 30g tank that's just now being introduced to marine salt for brackish environment.

[Flutter]

I haven't checked the size requirements for a GSP but I believe they're pretty large. Perhaps 30gal per fish which means you don't have room for a second puffer.

When will you be moving your other two fish as they aren't compatible with each other? You mentioned "gets" not "got" which means they must still all be together. Goldfish are coldwater fish and shouldn't be in with your tropicals. Plus there's the whole brackish issue too

[JayBMF]

I didn't plan on moving the other two fish since nobody argues about tank space. The second puffer I'll hold off on until I get a larger tank. My next size up will be 55g but that might be a while. I also read and have been told that Goldfish are fresh or brackish. The one puffer and the other two fish seem very happy. Especially the GSP since the top of his head is always fluorescent green. hee hee I haven't seen any symptoms of stress.

[Flutter]

Perhaps someone more knowledgeable can clear this up then

[Dadof4]

They more than likely will not get along and one will terrorize the other. When they are immature they can get along well but as they grow they become very territorial, even the fish you have in there now won't survive. Some people say it depends on the fish but from every account I've read with multiple GSP's the outcome is bad after they hit sexual maturity.

As it stands right now your tank is over stocked. 30 gallons per lone GSP is the recommendation. Seems silly for such a big tank for such a little fish but the bioload these guys produce is massive and the best way to control that is to dilute it, large water changes and over filtration. You should be doing water changes 50% a week with one puffer in that tank. Stunting is another reason for the bigger tank requirements, the hormone levels these guys produce is large also and needs the heavy dilution. Now, add in the other fish and you are asking for trouble.

One last point, these guys do get big and have a long lifespan. Most that make it to adulthood get to be around 6 inches long (minus tail) and about the size around as a Nerf football.