Muscle Inflammation?

[JohnDyer]

My rainbow shark is swimming around erratically, and a portion of the muscle attached to it's right frontal fin is swollen. It seems to be trying to swim, but the fin sticks out at a strange angle and it ends up flipping itself upside down. It will then gasp for air for a moment, and right itself. I've seen him repeat this several times within an hour.

He had fin rot last week, so I moved him to an empty 10 gallon tank for treatment. The fin rot is all cleared up now, and he was looking much better, but now this happens.

Is it possible for fish to have muscle inflammation? If so, what can I do about it? I have no medicine except some Jungle Fungus Clear, which I used to treat fin rot. I can buy medicine sometime today or tomorrow if necessary.

Sorry, no pictures. He's hiding behind the heater at the moment.



EDIT: Sorry, I should have included this.

Request Help

Tank size:10 Gallons (quarantine)
pH:7.3
ammonia:0
nitrite:0
nitrate:25
kH:?
gH:?
tank temp:79

Fish Symptoms (include full description including lesion, color, location, fish behavior):
Rainbow shark has a bent pectoral fin, slightly swollen where it attaches to body, no discoloration. Swimming erratically and flipping itself upside down. He had fin rot a few days ago, I quarantined and treated with Jungle Fungus Clear, and it went away.
Volume and Frequency of water changes:
25% (Started 4 days ago)
Chemical Additives or Media in your tank:
Sponge
Tank inhabitants:
1 Rainbow Shark
Recent additions to your tank (living or decoration):
None
Exposure to chemicals:
Jungle Fungal Clear
Digital photo (include if possible):

 

[snake007]

Whats your water parameters, tank size and tank mates?

 

[JohnDyer]

Water parameters in the main tank were 0 for everything except 40 for nitrates. I haven't tested the quarantine tank, I assumed the medicine would mess it up a little.

I have a 56 gallon freshwater column aquarium.
Inhabitants:
1 Rainbow Shark
1 Chinese Algae Eater
3 Green Tiger Barbs
6 Neon Tetras
1 Blue Dwarf Gourami
2 Male Guppies
1 Cherry Barb

 

[JohnDyer]

I'm off to bed in an hour, but is there anything I should do first? The fin I was talking about is the right pectoral, in case "frontal" is too vague. On closer inspection, it doesn't look particularly swollen, and the fist can still move it, but it is bent off at an odd angle.

At the moment, he is stuck in the upside-down position. He still swims around if I disturb the water, and quickly too, but can't seem to flip himself over.

Should I lower the water level? I am also worried that he may just pop out of the tank while zipping around. The tank's lid doesn't cover it fully.

Any help?

 

[JohnDyer]

Unfortunately, the little guy is dead... He was my favorite fish too.

But, I would still like to know what happened, if possible, so I can prevent this in the future.

RIP man 4 years, not bad. Oldest of all my fish, actually.

EDIT: Guy was censored out for some reason.