Is a 20 gallon tank big enough?

[Grublam_noraa]

I have a gsp and a f8 that are both about 1.5 inches. Could I leave them in a 20g hexagon tank for a couple years untill they get bigger? Posibly only 1 year. Also, I am working on changing the water to full salt ( at the lower end to accomidate the f8) so I can add a valentini puffer. Is this a good or ha idea?

[marksrush]

First of all, welcome to the forum!

Well, unfortunately the short answer is no. Part of the problem is your hex tank: they have a smaller footprint than rectangular tanks and this greatly reduces the amount of swimming room your fish have. (Most fish don't care about "up" and "down" swimming so tall tanks are more to please you than to please your fish.) You can probably get away with keeping them in your current tank for a couple of months, but beyond that you are risking the health and well-being of your puffers. According to the PufferPedia, your GSP should have a tank that's at least 30 gallons, and your F8 will need at least 15 - and bigger is always better. Another consideration is that your GSP will need high-end brackish or full marine conditions, whereas your F8 needs low-end brackish water...which means separate tanks. They would most likely need separate tanks anyway, as an adult GSP can be quite nasty and might eventually attack and kill the F8. That's not a "for sure" thing, but it's definitely a strong possibility.

Concerning your last question about adding a valentini, well a valentini needs at least 20 gallons to herself. A GSP will thrive in full marine conditions, so theoretically if you had a HUGE tank you could keep the valentini and the GSP in there together, but otherwise I'd expect the valentini to get beaten up by the GSP eventually. Keeping the F8 in full marine conditions is out of the question.

I hope that answers your questions. And again, welcome to the forum!

[LilGreenPuffer]

Yep, what he said. Welcome!