Bristlenose skin problem

Hi all :hi:,

I have had a problem in my 6ft tank for about 2 months now and I wondered if any of you might be able to advise me please?

I introduced some new fish into my tank and within a week little marks started appearing on my bristlenose plecs. They looked like little gouge/bite marks so we assumed that the new weather loach were a bit naughty and were the cause of the problem. Because it affected a few fish we moved the loach into their own sandy bottomed tank and thought everything would then be fine. It wasn't.

I can only assume that the loach brought something in with them as, over the last 8+ weeks we have still had continuous problems with the bristlenose plecs which begins with faint white marks on their backs which become pink over the next few days. It then becomes a bit like a small crater, spreads over the back and then the plec dies. There is no scratching or pecking that we can see. Fish still eating. Pics attached (I hope they work).

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[ame="http://smg.photobucket.com/user/gyp5y5/media/2.jpg.html"]2.jpg Photo by gyp5y5 | Photobucket[/ame]
[ame="http://smg.photobucket.com/user/gyp5y5/media/3.jpg.html"]3.jpg Photo by gyp5y5 | Photobucket[/ame]

I am in the UK. We have tried Myxazin twice, Protozin, Sterazin and am about to put the third and final dose of Octozin (double dose) in this evening. We have also been using Pimafix and Melafix. Water changes have been done between these medications and the correct length of time left between switching. Water parameters are excellent. 15-20% water change done every weekend. Lots of filtration (external and internal) and filters cleaned on rotation. Fed on Hikari wafers, catfish pellets and flake food. Lots of bogwood in there for hiding places. Had plecs for 4+ years and never had anything like this before.

Tank holds plecs, gourami, guppies, cory catfish and tetras. Only the plecs are affected by this skin problem which is strange. Also only between 1 and 3 are affected at any one time. Males or famales, different sizes.

Sorry it's so long but I thought I'd try to give as much information as possible from the start. I have to go to work now but I will *try* to get on with my phone during the day and will definitely be back on this evening.

Thank you so mush for reading and for any help you can offer me and my fishies.

P.S. One of the four new weather loach we moved seems to have some problem as he is shedding a slime coat regularly and is hanging out by the filters in the new tank. He has only just got ill though (in the last week). MUST be related to the plec problem, mustn't it?

It does look very much like bites. Are you sure that big pleco hasn't taken offence to the little ones?
Another thing I would be checking is shine a torch in when the tanks been in total darkness and make sure nothings coming up from the gravel and annoying them.

Hi, thanks for your reply.

The big pleco is so laid back and calm it's unreal. I agree they end up looking like bite marks but they start off like flat fungus-y markings that you can still see the pattern of the bony plates through. It's only after these come off that it ends up like bite marks.

We are trying our hardest to keep a close eye on any affected fish but there are quite a few pieces of bogwood in the tank so they have plenty of hiding places. I suppose it could be that they are getting the white markings on them (some on fins as well and always round (not Ich-like though, much larger)) and other fish are trying to help/can't resist a tasty snack and it's them that are making it all much worse.

I need to find out what I can do about the initial white mark stage to see if I can stop it before it develops but we're tried Myxazin, Protozin, Sterazin, double dose Octoxin, Melafix and Pimafix with no affect whatsoever.

It's probably something really simple but it's beating me! :wb:

Strange. You could try some salt in the tank. Probably will ease the troubles but how to get to the bottom of it and get rid of it I don't know.
I would have thought the protozin would have fixed it?

We have now set up a small quarantine tank which is currently holding 3 fish all with the advanced stages of the problem.

There are a couple of plecs with the first stage (small white markings) in the 6ft tank which we keep trying to catch but they are very quick on their fins so 6ft tank gets destroyed and no sign of fishy each time we try! haha Will keep trying though.

We thought if we could isolate the fish as soon as they show signs we might find out whether it's pecking from other fish that is making the whole thing worse and we're just suffering from some nasty fungus.

Going to do a 50% water change this weekend and we are seriously thinking about stripping the 6ft tank to get the undergravel filter out. We are starting to wonder whether there is something in there that is bad (had to do this a few years ago too as the undergravel started causing problems. Do *not* know why we put another one in).

Also, the sick weather loach that we think started this problem died yesterday. Slime coat peeling badly, black face.

Brengun, thanks for your reply. Is salt ok with Corydoras? Do you have to reduce the dose?

For salt you add it in stages over hours. Watch the corys and they will tell you if its getting uncomfortable.

When I had ug filters I would take the tops off the risers and slide my syphon hose down them and suck all that gunk out every so often. Sometimes I even found baby shrimp and corys under there.

Do a bit of a gravel vac as well but not all the tank at once as you don't want to upset all of the bacterial balance at one time.

If doing a large water change, add back the new water over time. Maybe even in stages so it doesn't shock any already stressed fish.

Make sure with the new water you treat it with seachem prime or something. Never know what is in town water nowadays and at least prime will help protect the fish.

Thanks, Brengun. Some really good advice there, particularly about sticking a hose down the pipe. Will try that instead of stripping the tank to remove it.