I do not have water test results yet, but will post them ASAP.

I have a valentini puffer in a 29 gallon tank with a sixline wrasse, and bi color blenny. I have had the puffer for about 3 months. No disease or sign of illness since I have had him. Has been a healthy eater, diet consisting of mostly mysis. I turned on the tank light when I got home, and he was in his normal sleeping spot. About an hour later, I went it to feed the tank and could not find him. I found in near the bottom of the tank (not on the substrate) and he is puffed up! I have never seen him like this. I have never noticed either of the other fish harass him, and he did not puff up when I turned on the light. This will sound dumb but I thought only true puffer fish could puff.

Am I just being a panicky fish mommy, or is he in real trouble?

I dont know much about puffers as I have never kept one but from what I have read on them they tend to puff up when stressed or as a defensive measure. So I'm assuming something may have caused him to panic and so puff...

I dont think it would be your water as otherwose it would have already been puffed up when you got home unless something drastic happened to your water after you got home...?

Panicky, as long as he's in the water while he puffs then he's fine...the worst case scenario would be if he's puffed due to stress. Keep an eye on him, should go down. My f8 puffer blew up everytime I fed him...of course I was pretty aggressive with the feeding stick. And yeah, all puffers puff

The closely related diodonts (or balloon fish) are known to puff up "for no reason". On the other hand, I once had a very sick figure eight puffer that puffed up the night before he died.

It's probably nothing to be concerned about. Hell he could even be just doing it for fun or some kind of stretch.

Sad to say he was dead this morning. Not sure what happened...had no sign of illness...tested water stats... amm 0 nitrites 0 nitrates 5 The other fish seem to be fine. Thanks for the help, though.

Sorry for your loss.

OUCH! Thats a shame and I'm sorry to hear that. I still think something startled it after you put the lights on that caused it to puff up if all the params and everything is fine. Very strange...

1entra, always chasing the wild goose

My hypothesis is that it was a mantis shrimp. But... no ordinary mantis shrimp. This one has LASER GUNS... and can fly and run at the speed of sound. Also... it is both invisible and invincible. Finally... it commands armies of corallivorous bristleworms. It's horrible, I tell you.

I'm actually going to suggest that what killed the puffer was a stroke or heart attack, seeing as though your water is fine. If so it was not your fault in the slightest. Again, sorry for your loss.

Well somebody has to...