Neon Tetras - diseased fish?

Question
QUESTION: History:
I have been running a 5 gallon freshwater tank with live plants and 7 neon tetras for 1 year.

The Water temp is at a constant 78 degrees, ammonia levels = 0, gravel is vacuumed and a 20% water change is performed weekly

I've had one death 3 months ago - (possible neon tetra disease - white spot on body, trouble swimming, other fish were avoiding him on his last day)

Current Problem:
Fish 1: Neon has developed a dark black lump on the side of its abdomen. It is swimming normally/eating/schooling with the other fish. It doesn't rub against rocks and no fish are aggressive towards it.

Fish 2: Neon has developed eyes that bulge out of his head. His swimming appears to be labored but is still schooling with the other fish. I just noticed these symptoms so I'll have to monitor his eating over the course of the day.

Could the current sick fish have been infected by the one that died 3 months ago? Or does it sound like they have some type of bacterial infection and/or tumor?

Would you recommend isolating the sick fish in the same hospital tank? Or setting up two hospital tanks?

Are there any OTC treatments I can administer in the hospital tank?

Any help would be greatly appreciated :)

Thanks!

ANSWER: EDIT: Hi
I was looking for something else, and stumbled across this info on a raised black lump.  Not sure if it applies to your fish or not, but thought it was interesting.  Scroll down to Black Spot

http://www.angelfire.com/poetry/canadasangel/FishDiseases.html

I don't know how reliable that site is, but some of the info that's posted I've seen on other sites.

Christy



Hi Amy
The black lump....no idea for sure what that is.  Tried doing a searc on that, not much info on anything like that.  My guess would be possibly a virus, an internal parasite/worm, a tumor, or even just dead tissue.  

The one with the bulging eyes, that sounds like popeye.  That can have a few different causes, from an internal bacterial infection, poor water quality, etc.

If the previous fish that died did have true neon tetra disease, usually it's transmitted to other fish when they eat the remains of the dead fish.  It's the spores that are inside the infected fish that are contagious.  
Do/did the fish look like their wasting/bellies look thin?

It's possible it could be from the previous fish that died, and it's just taking on a different form with these 2.  It's hard to say really though.  I would go ahead and QT them to be on the safe side, and put them together.  Honestly, neons aren't really the hardiest of fish, though yours seem to have done well if you've had them that long :)  You could try treating with a antibiotic and an antiparasite med, that should cover all possibilities.  If you're in the US, the Mardel line of meds should be ok to use, and they can be combined together safely.  I would recommend Maracide and Marcyn Plus, or if another brand that's equivalent to those 2.  Or if you prefer, try the antibiotic first and see if that clears them up, if not try the parasite med next.  
I'd also recommend picking up a test kit to also test for nitrites and nitrates.  Nitrites should be reading 0 ppm and nitrates under 20 ppm.

Good luck with them.

Christy

---------- FOLLOW-UP ----------

QUESTION: Hi Christy,

Thanks for the additional info. The neon tetra with the mysterious black spot/lump ended up having True Fungus. He was behaving normally (eating/schooling) for about a month until just recently when the black lump grew a cotton-like patch resembling mold - the lump now has an what appears to be an ulcer.

I'm surprised the fish lasted so long with this fungus - most websites claim that fungus will kill the fish in a matter of days. I wish I had been able to ID the disease sooner. But now I know for the future.

I bought Pimafix (to cure the fungus) and Melafix (to heal damaged gills). We'll see how that works.

Answer
Hi Amy
I don't think that's a true fungal infection. Usually fungal infections are secondary to another infection or problem.  There's a bacterial disease called columnaris.  It can resemble a fungal infection.  It actually has a wide variety of symptoms, from cotton appearance around the mouth, tail/fin rot, white slimey strands, skin can look like it's peeling.  Here's a link that explains it more.  If the lump now looks like an ulcer, I would say that's probably a bacterial infection.  Or it's still possible it was some kind of tumor that "opened" up so to say.  Try the PimaFix, I've had good luck with that for various problems, but if it doesn't improve in a few days I would go ahead and also use some Maracyn Two along with it-they're safe to use together.

http://www.flippersandfins.net/flexibacter.htm

Christy