Just got back from the store with a dwarf puffer, only to find out it's not a dwarf puffer. It's actually a green spotted puffer, which requires very brackish water and gets quite a bit bigger (up to 7 inches).

I am still determined to keep it. With a little research it shouldn't be a problem (at least not until it gets bigger).

Sort of mad at myself for not checking into this more first. I wasn't sure if this was a dwarf puffer or soemthing else, but I did know the dwarf had a few other names it went by and figured my tank was better than nooppee's either way.

Another uh oh. I also bought four little otocinclus to put in there with the puffer. I don't know if they go well with green puffers or not, but dwartpuffers.com suggested them as tankmates. Anyway, I just noticed one of the four is missing an eye. Not really a big deal, I guess. I predict he'll be a victim of the puffer eventually, though, sneaking up on his blind side and taking a big bite out of him.

Ottos can not tolerate brackish water, and are not compatible with green puffers at all, as you have already found out. Please separate them or bring one species back to the petstore. Keeping them together while the puffer can eat/harm the ottos and the puffer in fresh or the ottos in brackish is a little on the cruel side.

Well in that case,maybe you shouldn't keep the Oto's in the same tank.If I thought that I was putting a vulnerable fish into a tank with a fish that would tear him apart- I wouldn't do that.
If you have to keep this tank alot more Brackish for this type of Puffer,will the Oto's still be able to handle the salinity? From what I read,they are freshwater and don't like salt.
Oto's

My prediction turned out to be correct, and rather swiftly. The half blind oto was just crunched to pieced by the puffer. The otos are being separated as I post this.

Poor otto, he didn't even have a chance

Here is a site for the puffer:
http://www.aquahobby.com/gallery/gpuffer1.html

The otos don't appear to be out of the woods just yet. I put them in my 55 with three goldfish and I think one of them was sucked up by my biggest fish right after he went in the tank (they tried to get him, but they chased him behind a fake rock thing so I couldn't see if he made it away safely). I am able to see two of them, but one appears to have a small bite taken out of his back.

I'm going to try and catch them in there and put them in my third (and last) tank. There are goldies in there, too, but they're much smaller.

Large goldfish will eat the ottos too...as you have figured out again. They have spiny dorsals that can get lodged in the goldfish's throat. How big are your smallest goldfish? I hope these ottos aren't carrying any diseases because all of your fish have been exposed now.

I suggest keeping them in a rubbermaid by themselves for a quarentine, and so the survivers can settle down.

Thanks for the link. I'd been trying to find out how much space they really need. Looks like I will probably have to end up getting rid of it after awhile, as a couple different people there mentioned 200 liter (55 gallon) aquariums. Right now he's in a 10, but he is still little. I'll hold onto him for awhile and hope for a bigger tank to come along. I have no idea where I'd put another tank, though. I already have 75 gallons of water in my room.

The otos probably do have diseases and will end up killing all my other fish... ######. I didn't even think of that as I was worrying about getting them away from the puffer. I guess that's what the other fish get for trying to eat 'em....

Just be sure to watch all your fish closely for any odd behavior and make sure their water is extra clean. They were only in for a little bit and some fish seem to be more immune than others so just be prepared. I bought a few black neons from a tank that had rasboras covered in ich. None of the tetras had it, and the ones in qt or the gourami with them have yet after 2 weeks.

Ok, the green puffer is currently isolated in a 10 gallon tank. If I keep him for good he'll probably need a 29 at least, which I may or may not have room for. The otos (or what's left of them, about 2.75 fish all together) are in my other 10 gallon on their own. My two goldfish that were in there are now in the 55 with my three larger fish and seem fine, although one of the two seemed a bit scared of the big ones at first.

Everything seems fine for now. I've heard otos can have a pretty high mortality rate early on, so chances are one or two would've died soon anyway. Because of the way things worked out, they're in a tank with no algae to eat and they haven't touched the algae flake things I put in there. Hopefully they'll enjoy some green vegetables tomorrow.

Sounds like a good temporary set up Don't worry about the small goldfish unless they are small enough to fit in the big one's mouths. Hopefully the ottos will perk up and eat in a couple days once the have relaxed a bit.

Try setting some stones in a bucket of water out in the sun. After they start to grow algea on them, bring a few in for otto food. You can rotate the stones in and out of the bucket so you'll have a constant supply of green algea.