Hi - a few weeks ago we noticed that one of our lemon tetras has some dark marks on it's tail and dorsal fin. Some of the other lemon tetras have now also got a small amount of this. We went to the LFS and described the markings and they gave us some Interpet Anti-Internal Bacteria to try. We have done the recommended 2 doses 4 days apart and have seen no improvement. There don't seem to be any other syptoms - the fishes are all eating well and swimming about quite happily and I haven't noticed any flicking.

Does anyone here have any ideas on what it could be please? I have attached a picture.

Thanks

Could be part of their colouring. did you get them at a young age?

We've had them for about 18 months and their tail fins have always been clear so I don't think it's part of their colouring unfortunately.

What colour are the marks.
Can you describe the texture of the mark.
Do the resemble a cauliflower.
Black patches on fins are ammonia burns that are healing.

Sorry can't make much out in the pics.

This post has been edited by Wilder: Jun 23 2008, 08:37 AM

Hi Wilder. They are very dark grey/back marks. Hard to see what the texture is but it does stick out from the fins. As I said the fish don't seem bothered by it at the moment but it does seem to be spreading to the other lemon tetras.
That's the best picture we could manage I'm afraid.

Do the patches look like growths.
Growths of the fins that look like a caulifower or cluster of eggs is lymthocystis.
Any signs of flicking and rubbing.
Any laboured breathing with your fish.
Black marks on fish are ammonia burns that are healing.

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

I would also post this thread in tetra part on the forum to see if they know what it is.

This post has been edited by Wilder: Jun 24 2008, 04:17 AM

I'd say they look like growths rather than just black marks. I haven't noticed any flicking or rubbing.
The tank is 240 litres - 9 lemon tetras, 12 cardinals, 1 platy, 6 corys, 2 SAE, 3 Ottos. No Ammonia or nitrite, nitrate is 10 and pH 7.

I would take a look at this article to see what you think.
Usually the growths are white, pink or brown, not sure on black growths.
http://www.aquarticles.com/articles/manage...mphocystis.html

Hmm that's interesting thanks Wilder. I'm not sure if it is that but it could be - it does say that the virus only effects the hostfish or some additional closely related fish so I guess it could effect more than one lemon tetra. Doesn't sound like there's much I can do about it though so I'll keep an eye on them for any secondary infections.

If there any changes get back to the board.
Good luck.

Hi melh

don't take this the wrong way but boy does that fish look unwell.
it's bloated, has a white patch on its head above the eye, has black marks all over its fins & caudal peduncle, and looks like it has whitespot on its tail. It also appears to be covered in a grey film, most notibceable across the top of the body.

If the fish are 18months or older then they are getting on a bit but I think the problem is either poor water quality or a skin parasite like chilodonella (or something along those lines).
I would get the LFS to check the water quality, especially nitrate and do daily 50% water changes and gravel cleans for a week. See if that helps. If it doesn't then treat the tank with something like "Waterlife Protozin".

The grey film on the body could be the skin parasite or poor water quality. The black patching on fins & body is most likely bruising (cell damage) as suggested by Wilder. The white above the eye and bloating is probably caused by poor water quality or the fish is suffering from a major ailment, (possibly an internal infection).

It isn't Lymphocystis, so don't worry about that.