Probably another case of Microbacterium marinum or commonly known as TB. Is generally not treatable. The same drugs for treating human TB can be effective on fish. It can transmit to human through open wound or cut in your hands and manifest in the form of nodules around the cut. The symptom may take 2 to 4 weeks to surface. Most of the time your immune system will take care of it. In rare cases, if the infection is deep in the tissue, surgery will be required to cut off the infected area if drug treatments are ineffective.
This is what the book said-quote
a parasitic disease primarily of cichlid fish, some authorities consider that most, if not all aquqrium cichlids are infected. the parasites are readily transmitted from cichlid to cichlid.
White stringy Poop, sometimes also but not always,accompanied by enlargement of the sensory pores of the head, which usually also become filled with whitish pus.
Dark colorization and loss of appetite are common in advanced cases.
Both emancipation and distended body have been reported
These weakly pathogenic parasites are commonly found in small numbers in the intestines of cichlids, where they do no apparent harm under normal circumstances.
If however the fish is weakened (e.g. disease,stress,environmental problem) the parasites multiply and migrate through the fishes system.If (and only if)they reach the sensory pores do the characteristic pus filled holes develop
Death occurs if a vital organ is invaded and fatally damaged.
Many mystery deaths of cichlids may be due to hexamita infestations where the sensory pores have remained unaffected.
As i have already said, i had not come across this disease before but i was amazed to find the exact symptoms that i had with my rams.I am sure the medication has worked for me and i will continue to use it , i also went and bought the book.
With all that being said, I would get that fish out ASAP. I would also recommend putting in something that the fish can hide in (flower pot), because once moved he\she will be stressed.
I would use garlic to feed them to help with the immune system. And look into a few things. What you will expect to see once this has completed is the following..
The bump we will call it a pimple. Once it pops it will eave a giant hole in the head, and the parasite or badness in that bump will go all around the tank and infect.
When you take him out, use another net (you do not want to cross contaminate the net)
I would look for an antibacterial thing, in the meantime - I would dose your tank with Melafix (that will help kill bacteria, and might help - I noticed when I used this for other type of bacterial infections it would clear up in a day or so) but if this is fish tb, strong chance the fish will die.
You also need to bring that PH down! 7.5+ is BAD!!! I used to keep my PH around 6.8-6.9 for my rams, and noticed they didnt live past 3-4 month range. Since I lowered my PH to about 6.2-6.3 i have yet to have a RAM death.
Water changes and water changes! and vaccum as much as you can. Do a test on the water and report back with your parameters! This will be an imporant thing, because if the water quality is bad, this could be the #1 reason why he\she looks like that.
I apologize about the he/she - i was not paying attention to the fish's sex. From what I recall it was a female.