Periodical white zit on goldfish      1/22/14
Hi again, Sorry for emailing again, but I thought you might find some photos useful.
These are from this morning. The zits are not yet white, there is no colour difference with the rest of the scales, what you can see here is an effect of the light
reflection. Https://www.dropbox.com/sh/rsan1908pro3jc1/ZUtSeUp6G4
Thanks again.
Lauren
<Can sort of see "something" white, everted>
Hi there! I am very new to this, so first I'd like to thank you for your great website, I've been learning a lot by reading through! I'm writing about my comet goldfish who had some problems for about three months now. Here is my set up: I have a 45 Gallons tank, it is planted, has rocks and pebbles of various size, and two pieces of driftwood. The cycle has been established (and the fish then introduced) for 6 months now, and the water parameters have been stable to ammonia 0, nitrites 0, nitrates between 10-20, ph 7.2, temperature around 20C (I don't have a heater, so it's room temperature). There are 4 filters in the tank (2 small ones from my previous tank, both around 120L/hour - I put them there to help the tank cycle and left them there - and 2 bigger ones, a Fluval C4 and a powerhead which is connected to an airpump and which circulates a "river manifold" in half of the tank, so it also acts as a filter). I perform regular water changes, 30% every week, and I test the water every week.
<Good>
 I have had the goldfish for a year now (in another tank for the first 6 months), so he is still pretty young and only 3 inches. Along with him in the tank I have 3 white cloud minnows, 2 Hillstream loaches (Gastromyzon scitulus) (which is why I have a river-like tank), and a tiny snail of unknown coldwater specie (I used to have a bigger one, but the goldfish ate him last week). I feed them blanched greens alternating between kale, broccoli, lettuce, green peas, cavolo nero (I try to feed greens regularly, almost every day or every other day), and alternate goldfish pellets, Spirulina pellets, goldfish flakes, and give bloodworm and daphnia as an occasional treat. The goldfish poop has been looking not so good for about a month, the consistency is right but about half the time it's greyish/whitish (the rest of the time it's the colour of what he eats).
So here is the main problem: For the past 3 months my comet has been developing a bump on his left side (the scales don't raise, it starts without sharp shape, about the size of a grain of rice but smooth under the skin and no colour difference with the rest of the skin); after few days the bump becomes more defined and localized, the edges sharper and rounder, but still no scales raised or colour gradient/difference with usual scales; then after few more days it progressively protrudes out to a white eruption (really like a zit), then bursts, letting the white come out, and then heals very quickly, as if nothing happened. From the time it appears to the time it explodes it takes exactly 7 days. This has happened 3 times so far (so about once a month), always on his left side, about in the same place, but not exactly. The zit doesn't move once it starts forming, and gets to a maximal size that is smaller than his eye. One started forming again 3 days ago, but I've just noticed there are actually two bumps about 1cm apart now. He doesn't seem to mind at all (except at the moment when it burst, when he flashes for few minutes, but that's it), he is very energetic and eats well, he is super curious (he goes crazy at me every time I get close to the tank, which makes it hard to take a photo). The rest of the fish are really doing great, for now.
I've tried to read online, but I just managed to confuse myself. From what I understand it could go from bacterial infection, to viral infection or some protozoan parasite. From what I got, using aquarium salt would probably be a good start, but I wanted to check what your opinion is before doing anything. If it's parasites I should probably treat the whole tank rather than set up a hospital tank (right now the only extra thing I have left is a 12-litter tank...)? If I do use salt, what should I expect to see as improvements? Should the zit not burst? Should I wait for the present zits to burst and then add the salt and hope it doesn't come back? Thanks a lot for your help, and please let me know if you need any extra information.
<Well; this could be a few things; but my best guess is that the spot/area is a wound site... the goldfish got snagged on something... perhaps the driftwood; and this sore developed. There is some small chance that a pathogen might be involved (mostly secondarily); but in all cases; knowing what you've stated here, I would NOT treat the system/water. Better to wait, see if this "tumor" abates of and by itself. Bob Fenner>