The Puffer Forum

This is my 1st post to the forum, and let me say in advance that I appreciate that I appreciate everyone's help.
Just before Christmas we purchased a used 120 gallon, freshwater tank that was already stocked. There is a conglomeration of fish that don't seen to go together, but they are all coexisting without any fatalities. I will list the inhabitants of the tank at the bottom on the post.
The reason for my post today is probably our favorite fish in the tank, a small Green Spotted Puffer. We were told that the fish was 3.5-4 years old, but only measures just over 2" long. I didn't take him out to measure him because I didn't want him to puff up, but we got him over to the side of the tank and measured him that way. All of us have been researching different sources on the internet to try to find out what we should be doing for him, but there are many differing opinions. I stumbled upon your forum and everyone seemed to be very knowledgeable and conscientious.

Here are my questions:
1. Could his growth have been stunted by either leaving him in freshwater all of his life or by possibly not being fed correctly when he was young?
2. We are concerned about his feeding schedule. We are reading that juveniles need to be fed every day, but that as they get older that you can cut that down some. Even though he is so small, is he considered a mature fish? How should we be feeding him? We have even setup a 5 gallon tank to try to breed some snails so we can stop going to PetSmart to ask for theirs.
3. We are also reading that because of how aggressive the GS Puffer can be that they should be in a specimen only tank, burs seems very docile and I can't imagine him hurting anyone. Should he be moved by himself? I know that the recommended minimum tank size is at least 30 gallons, but I have a 20 gallon that I am cycling to try to start a saltwater tank. If he needs to be moved, could I use that tank since he is so small?

Tank Mates:
Blood Parrots x 2
Black Convicts x 2
African Leaf Fish
Angel Fish x 3
Electric Blue Acara
Black Skirt Tatra x 7
Tire Track Eel
Black Ghost Knife

Wow, you do have a very odd mix of interesting fish in there! I'm quite surprised the puffer isn't terrorizing all of them.
library/puffers-in-focus/an-introductio ... d-puffers/

I have read that they would normally harass their tank mates. We were just assuming that he is leaving them alone because he is so small. With the exception of the Tetras, he is the smallest thing in the tank.

He's still an adult though. You asked about his size because he's in FW. You are correct, I'd assume that's why. Are you planning on moving him to BW?

That was one of my questions. He seems happy where he is, but everything that I have read says that he will live longer in BW. I have a 20 gallon tank that is almost cycled with SW that I don't think would be hard to switch to BW. Is that tank big enough for hi with his size? Will he be happy to move to move from such a large tank? What is your opinion?
Also, how often should we be feeding him?

Minimum size for a GSP is 30g, although they'd be happier in a 55g.

Since he is an adult, how often and how much should we be feeding him?

6 days/week