The Puffer Forum

I got this guy a couple of weeks ago. He was doing fine this morning, but now hes sitting on the bottom, he looked dead so I gently poked him with a net and he tried to swim around but it didn't last very long and he fell back to the bottom. He's in a 10 gallon with 3 endlers, who have been in there for more than a month, a bamboo shrimp and a columbian ramshorn. Nitrites 0, nitrates ~ 30, pH ~ 7.8.
Any help would be great, thanks.

Ammonia? Temp? Water changes? There's nothing in the tank animal-wise that would have killed him.

Ammonia 0, WCs 50% weekly, temp 78.
He's not dead yet, but looks close to it. He was eating and swimming fine yestersday.