Hillstream Loaches & Oranda - discoloration and sudden death

[Little-AL]

Hi Guys,

I purchased 2 x Hillstream Loaches and a small Oranda from a local LFS (that I have never used before but have quite a good rep from what I can gather) - brought them home and got them settled in to my tanks (Oranda in one tank with another small Oranda that I already had and the two loaches in my larger tank - already has one small loach, a few oranda and some gold minnows).
Noticed yesterday (Sunday) that the oranda had an odd white mucus type coating all over its body - it was just sitting on the gravel and not doing very much at all.
Both loaches had a white coating over parts of their bodies (could just about make out their markings).

This evening when I returned home from work the Oranda is about the same - not eating, not moving - when caught in net it didn't move or flap - just very slow breathing...
Both Loaches were dead - they had gone nearly totally white (I can upload a pic if it will help).

I have tested water and both tanks are: PH 7.4, Amm 0, Nitrite 1ppm, Nitrate 5ppm. All of my other fish are fine, the other loach in my tank is also fine - skitting around as usual, no discoloration etc. Same with the rest of my fish - all are absolutely fine - no visible disease, all eating and swimming as normal.

Now the fish that I bought were kept in separate tanks that I would assume are all linked through one large filter/sump system in the shop - is it possible that they were all carrying some form of disease and introducing them in to my tanks has brought it out? Should I start dosing my tanks with medication to make sure the rest of my fish stay ok?

Any help or advice would be great as I obviously don't want to lose any of my other fish!

 

[jsoong]

It is likely that the lfs has one central system for all their tanks. Even with separate tanks, it is easy to cross contaminate in a busy shop. So I would assume that if one tank is sick, all tanks are sick in a lfs.

Your nitrite of 1 ppm is not good. Are you sure that is an accurate reading? <I would expect symptoms in your other fish at that nitrite level, unless you have salt in your tank.> At any rate, that is the first thing to sort out. To keep fish healthy, you must have clean water. Having high nitrite is not going to help.

I think the first thing to do is to do a large water change & good gravel clean. Whether the nitrite is real or not, clean water & reducing organics in the water will only help.

White mucus is due to thickened slime coat. This can be either heavy parasite infestation, or more likely a bacterial infection. <Esp. with the symptoms you are getting.> You might consider doing a salt bath to stripe off the slime coat in the sick oranda to reduce bacterial/parasite load, although a weak fish might not survive a salt bath.

I would be treating all the fish with a course of anti-biotic food as prophylaxis. In the future, always QT new fish, no matter how reputable the lfs is .... it saves a lot of trouble down the road.