The Puffer Forum

As for temperment these guys get along great with other fish, and can be actually a bit of a push over.

They can also easily live in a 20 gallon so long as you have it set up correctly with live rock and a good filter.

We recommend a minimum tank size of 25g for a number of reasons.

I can understand why you would say a min. of 25 gallons is needed, but a 20 is just fine.

I think it's quite hard to define what is 'just fine' for an animal that can't communicate to us how it is feeling easily. Judging on my Valentini's personality, I wouldn't put one in less than a 30 gallon tank, because he is quite active and gets bored easily. Also, I have seen full grown Valentini's that are over 4 inches in size, and I think it would be cruel to keep a fish that large in a tank less than 30 gallons. Also, as I think Boxermom was alluding to, puffers are messy eaters and in a tank of a smaller water volume the parameters aren't as stable which could lead to spikes in pollutants.

How long have you had your puffer for? And how big is it?

I'm not trying to have a go at you at all, just expressing my opinion.

Mine loves to investigate the whole 40g he's in.