danio with odd lump

Question
I have a jaguar danio and have noticed in the last couple of days it has developed a strange lump on one side, near the back of its belly towards the tail. The lump is whitish and blobby, it appears have lumps on the lump. The belly is also very swollen, but the lump is quite big. Do you have any idea what can be wrong? The other danios seem to be fine and i am worried that this will effect the others, should i separate the danio with the lump? My tank is medium size holds about 40 litres, i change the water once every week, usually about 20 litres. The water often gets a little bit toward acidy and i add ph up, but follow the instrytions and do not add too much. The water temp is 25 degrees as i keep them with my tropical fish, but was thinking of moving them to the goldfish tank, cold water.

Answer
Hi Kate
Most fish can handle ph ranges from 6.0-8.0 just fine.  The ph up/down products usually are only a temporary fix, and what happens is they may raise/lower the ph a bit, but if the water isn't buffered along with the product, it'll cause the ph to crash or rise very quickly which will stress and or kill the fish.  I'd recommend not using that product anymore.  How low is the ph dropping?  If it's bad, you'd be better off using something else to raise the ph to a better level.

I also wouldn't recommend moving them in with the goldfish.  Granted, danios can handle a cool water temperature, but goldfish tend to put out more ammonia naturally, just not a good idea to mix community fish with goldies.

Any chance of getting a picture of the lump?  If so, send it to christiie911@yahoo.com and just put fish picture or something like that in the subject. If you have another tank you can use as a quarantine tank, I would do that for now.  Hold off on feeding him/her as well.  

Here's a site, doesn't give much information though, but if you look at the third picture, white male betta and the caption, that kind of sounds like maybe what your fish has:

http://www.fishjunkies.com/Disorders/lumps.php

I can't picture exactly where the lump is, if it's on the bottom area, near the vent(where they poop), I'm wondering...it's common for danios and a lot of egg bearer fish to become egg bound.  I wonder if somehow the eggs are stuck there-if that makes any sense?  Do they look like they'd be the size of an egg(small) or a bunch of them together?  If you're up to it, you could try to remove it. It'll be hard with a small fish though, and probably even trying to catch it lol.  Get a small washcloth or towel, dampen it with some tank water and gently hold the fish.  You have to be quick though, because they need the water to breath.  If you have to, dump her back into the tank for a breath.  Use a Q-Tip moistened with some some peroxide or even just some tank water and very gently wipe at it and see if it comes off easily.  If so, scrape it off.  Dump her back in the tank, and very gently rub her belly area, especially where the eggs would come out with the damp Q-Tip(probably use a different one for this).  If she's egg bound this can help stimulate the eggs to come out.  If you do this, I would also advise adding an antibiotic to the water as well afterwards if you have them by you, or some kind of antibacterial agent like MelaFix and/or PimaFix.  If you don't have a quarantine tank, I would use a bowl with some tank water while doing this, that way if you need to put the fish in the water for whatever reason, it'll be easier to get back out.

Christy