Dempsey HELP!!!

[princess24]

Ok I need some help here... I have a Jack Dempsey that has a bubble type object in the front of his mouth. Half comes down from the top lip and the other half comes up from the bottom and they meet in the middle. He hasn't been able to close his mouth because of this nor has he been able to eat. Also by his gills he looks like he is having a problem breathing. He is swimming around but not as much as usual. Oh yeah I forgot that his belly is like a white color possibly from the loss of oxygen. Has anyone heard of this? Can someone please give me some advice?

PH is kinda low and the Nitrates are just a little high
I do water changes every week.
I had a problem with the amonia and the PH being way to high and put some PH decreaser in and some stuff to take the amonia out and a 25%water change(Fish having problems before I done this)
He is in a 45 gallon tank by himself. Had another small Dempsey but he died from Ich about 2 weeks ago. Recieved small Dempsey (deceased)about 2 months ago.

 

[Tokis-Phoenix]

How long has the tank been set up for and if it hasn't been setup for very long, how long did you wait before adding fish?
What exactly are the nitrite, nitrate and ammonia levels?

What color is the bubble on his mouth and is there any texture to it?
Does it look like anything in these links;

califlower desease

http/www.fishpalace.org/lymphocystis_2laaofa.jpg

http/www.fishpalace.org/lymphocystis_pas...hotmail.com.jpg

fluid filled cyst

http/www.fishpalace.org/cyst2_nickaustin_nick@ustin.tv.jpg

It could also be gas bubble desease where the cysts realy do look like small bubbles of air in the fish's skin...