Sick yellow tang

[kwan]

My yellow tang has been in hyposalinity treatment about two weeks now. Although he has been feeding well in the QT, his colour has gone very pale. And last night I notice he has a redish/browish spot developed just above his anal fin. You can probably just see it in the photo (not a very good photo though). It is more like inflammation.

Should I do anything about it or just leave it and let it take care of itself? And is it normal for it to be so pale?

I have not been able to make accurate measurement of NO2 and No3. They have shot off the roof. I am not sure whether this is caused by the copper I used earlier before I began the hypo treatment. I have changed water many times and in large volumes, but the results still goes off the chat. It could be remanent of copper in the internal filter I am still using. I have used a copper test kit and reports no level of copper at all. So why is my results for NO2 and NO3 are incorrect? If the NO2 and NO3 are really that high, then I would expect the fish have died by now or experience extreme discomfort. But there is no sigh of stress at all.

 

[steve-s]

Add some carbon or a polyfilter to the filter chamber to be sure it removes any remnants of the copper that may be left. The water changes should have removed most already (hopefully using well aged SW). I would also suggest testing your source water to determine the accuracey of your test kits. If there is much of a reading there, either the test kits are faulty or your source water is fouled.

When performing hyposalinity it is also very important to monitor alk and ph. They have a habit of not staying in the right range and need adjusting. A good marine buffer should fix that after you test to confirm. Low ph will result in the red markings you describe. It could be also be lympho combined with a bacterial problem if the water conditions are as high as you describe.

Test the ph and get the NO2 & NO3 confirmed.

Cheers
Steve

 

[kwan]

Thanks Steve! I am already using carbon and polyfilter and the copper test kit also confirms no remnants of copper. What is alarming is that the test kit results for my source RO water and for my display tank are fine. But I cant believe my QT water has so high NO2 and NO3 readings. I have been making big water changes like 50% and the readings still rocket high. I just donut understand it.

Otherwise my pH is fine now, I have been buffering it. But it did fall low for a couple of days whilst I was away on business. So the red marking might be a result of a drop in pH.

I just notice another white marking on his pectoral fin. I think it has been there since the red marking showed up. The white marking is very difficult to spot because I have to look at it directly against the light. Otherwise you wont notice it when the pectoral fin is closed up beside the body. It doesn't look like fin rot though. Could this be a result from low pH?

 

[steve-s]

Fish will get different patchy area's on their fins that will come and go. Not all blemish's are cause for concern. If it does not appear to be fungal or a parasite, I would not worry as yet. You still have another two weeks for the treatment anyway.

Keep monitoring the ph/alk and after a short time you should see some improvement in the tang if maintained, especially if feeding vitamin soaked foods. Keep up with the water changes and be sure the carbon and polyfilter are rinsed/changed regularly. Depending on the size of the QT you should only need about 1/3 of the polyfilter at a time so it will be just as economical to simpley change out for a new one once a week. They will trap detritus and such easily so be sure you are also syphoning out uneaten foods and the fish waste after each feeding.

Cheers
Steve

 

[kwan]

The red marking has spread, and is more like patches on the body. The white marking on the fin has rotted away. It looks like fin rot to me. What should I do?

 

[steve-s]

If your absolutely sure the water parameters and ph are good and have been so for a time, then I would begin with the Maracyn II at double the dose daily for seven days. Just be sure you medicate any new water for water changes as well to maintain the dosage. This will also destroy the biofilter so be sure to watch the water parameters carefully.

If possible, when you dissolve the med before each dose, take a few tablespoons of the medicated water and soak the food in it for a bit. That will help speed up the process some.

Cheers
Steve

 

[kwan]

Steve: I made a water change yesterday by replacing of the QT water with water from my main tank. And I also changed filter pads with ones I placed in the main tank a week ago to eliminate any remanent of copper. NO2 and NO3 were zero. I have not fed the fish yesterday but have began the medication. However, when I measured the NO2 again today, it has crept to about .3mg/la, NO3 remains zero.

Now what could be causing the NO2 spike. Should I carry out a water change everyday? How much water change is needed to bring down NO2, 20% or 50%? At the current rate of NO2 increase, the fish will probably die from NO2 piosoning before the fin rot will kill it.

 

[steve-s]

Now what could be causing the NO2 spike. Should I carry out a water change everyday? How much water change is needed to bring down NO2, 20% or 50%? At the current rate of NO2 increase, the fish will probably die from NO2 piosoning before the fin rot will kill it.

If using the Maracyn it is an antibiotic and as I warned you it will destroy the biofilter in the process. Daily water changes will most likely be needed for the next 7-10 days. I wouldn't use water from the main tank nor any filter media. Newly prepared and aged SW will be better as it does not contain any DOC. Change about 15-20% as needed but be sure the newer water is premedicated to maintain the antibiotic concentration. Filter pads from the main tank will be of no use as the antibiotic will detroy any beneficial bacteria. Once the med is done with do a large water change and add a polyfilter or carbon to remove any traces. Then place a something seeded from the display that will colonize the needed bacteria.

The red marks are the primary concern at this stage, the fin rot is just a sign of the problem advancing.

Cheers
Steve

 

[kwan]

Thanks Steve!