The Puffer Forum

Got a 5 incher and it was initially feeding on prawns/clams/snails...
A couple of days after releasing it into the main tank it developed some white fungus growths .. stopped eating too
Consulted the guy who imported it and he mentioned it was cause the weather in Singapore recently was cold - like 25 celsius at night..
A couple of days more the fungus thingy started on one eye - did a 30% water change -added salt, Melafix and Pimafix.
Died within 3 hours ... did I over medicate? Sad first try ..

Please answer ALL the questions in red above, so we can better help diagnose the issue with your puffer.

Sorry for your loss

Likely the infections were already present before you got him; the act of transporting him caused him to become stressed and that allowed them to manifest and take hold after a few days after his immune system was weakened. I had the same thing happen with some tetras recently. They were fine in the store but as soon as I got them home into an established tank they started getting the head fungus and refusing food and soon started dying despite treatment.

As for his last day it could be he was already almost gone and the water change and slight change in water parameters from the salt just put him the last but over the edge, even if you followed the dosing directions precisely, matched temp and pH and used treated water.

Also 25C is not cold for a puffer, that's only a few degrees off of optimal if im not mistaken.