Jack Dempsey sick?

Question
I've had a Jack Dempsey for about a year and just noticed that its color had turned very black.  It has been very lethargic and not eating.  It has been staying near the bottom of the tank and laying sort of "lop-sided".  Any information would be greatly appreciated.  Thanks!

Answer
Hi Jake,
I would like you to check your water first for ammonia, nitrites, and nitrates.  Ammonia, should be zero, nitrites, zero, and nitrates should be safe.  
You pet appears to have Swim Bladder Disease.  This disease is caused by constipation which went unnoticed, and is due to overfeeding, or poor diet.  Feed him cooked frozen peas, remove the outer layer.  If he refuses to eat the peas, you will have to treat him with a good antibiotic.  He must waste.  "Kanamycin" is very good for Swim Bladder, but is sometimes hard to find.  If you cannot find it buy Tetracycline, or Furan 2.  Remove your carbon, make sure your water chemistry is right before adding medication.  Follow the directions on the package.  This disease if left untreated may lead to Dropsy which is almost impossible to cure.  You must act quickly.
I hope the little man pulls through.
Lynda