Sick puffer?

[tqy]

Recently, I observed that my figure 8 puffer has been acting a little weird and seemed to have fattened immensely in size.

This is VERY unusual as he seemed to have literally doubled in size overnight. Upon closer inspection, it seems that his pectoral fins retracted into his body because I can only see a small portion of his fin. I also see a slight redness around the pectoral fins. Besides this, he also swims very clumsily as he misses bloodworms right in front of him and is also less energetic (but I wouldn't say he's lethargic either).

I feel like he's going to die soon and I would greatly appreciate all help I can get. >.<
Thanks a lot guys!!

 

[Brookster123]

What's up with the tank? Details

 

[tqy]

0 ammonia
0 nitrite
10 nitrate
Salinity: 1.004

15 gallons

No other creatures in the tank.

No changes were made to the tank for the past 6 months, besides changing my filter because the other one spoilt ( I brought the filter media over to the new one ) this was changed around a month ago.

http://www.aquariumadvice.com/forums/f17/figure-8-puffer-help-84406.html

Found a thread describing the same exact problems my puffer is facing. Clamped fins, redness around pectoral fins and clumsy movement. Unfortunately, no one could help in time. Does anyone have any clue as to what's happening to my puffer?

 

[tqy]

Did two consecutive 50% PWC and added 10ml of melafix in there to no avail. He seemed fine right after the water change but this is him 3 hours later, worse than ever. He seems to have puffed up even more and keeps swimming to the surface and floating upside down. Seems he is taking his last few breaths and I'm gonna lose him in an hour or so

 

[tqy]

Well, I found him dead this morning and he was really puffed up. His body was also abnormally soft when I touched it. Didn't find anything else besides the symptoms I described before. I'm really going to miss this cute ball of energy darting around in my tank