Preventative Hypo?

[Biggen]

Hello guys. I have been pouring over all the posts about Ich and the such and have a few questions. Can I simply run hypo salinity in my QT tank even though my fish shows no signs of ich at all?

In other words, can I run preventative hypo for the 4-6 week period my new Royal Gramma will be in his temporary home? Will this have any kind of ill effects on him? I know my LFS runs their tanks at around 16 ppm (perhaps to control parasites) but I know that they don't expect to keep their fish to longer either.

My second question is if my fish comes down with ich and I am running hypo, should I treat the tank with any kind of antibiotics? Would Maracyn or Maracyn-two be useful in order to ward off secondary infections caused by ich? Would these harm the biological filter? Or should I just use hypo and no drugs at all?

Right now my Gramma has been in his QT since Friday but I adjusted the SG to1.026 before I put him in. If I find out from you guys that I can go down to 1.009 for hypo, should I do it or just leave the tank at the SG that it is already set at.

Thx for any help guys...

[ATJ]

Preventative hyposalinity would work fine as long as the fish being treated can tolerate the low salinity - which appears to be most bony reef fish. I'm pretty sure TerryB does this.

Do you mean your LFS runs his tanks at 1.016 or 16 ppt? A specific gravity of 1.016 isn't going to be low enough to be of much value and a salinity of 16 ppt may not be low enough. It is also likely to cause problems for people buying the fish and taking them home. The fish will go from low to normal salinity in under an hour.

You should not need to run antibiotics with the hyposalinity. In the vast majority of cases the fish can recover from bacterial infections on their own. Antibiotics should only be used in severe cases. They are a risk to the biological filter and also it can result in resistant strains of bacteria.

It's really up to you if you want to use the hyposalinity. In my opinion, 6 weeks is long enough for "Ich" to show if it is present, but treating with hyposalinity guarantees it is not. Doing it will give you piece of mind.

[oama]

As to wether you should treat or not...
Depends or which school of thought you subscribe too.

One school says that all "new" fish are infected. So treat them!

The other school of thought is to quarentine the fish for at least two weeks. If they develope a disease, then treat it.

As to AntiBs...Don't OVER use them in Q systems! You could develope a resistant strain! If the fish get sick and you see 2ndary bacterial infections, then treat them. Never use antibiotics as a preventative treatment!

[TerryB]

I do recommend treating all new bony reef fish with hyposalinity therapy in quarantine for three weeks+ BEFORE adding them to the display. If you are using an ACCURATE means of measuring the salinity it will cure ich and help the fish recover from the stress of candling and transport. Check the pH daily in treatment.
Terry B

[Biggen]

Thx for all the responses guys. Yes, my LFS does run their tanks at around 16 ppt. If that is not low enough to control parasites, then I am not sure why they are doing it. Perhaps its to save on salt costs...

Ok. So bony fish are pretty well adapted to running at lower salinity. I think since i have already set up my QT and have already adjusted the SG to 1.025-1.206 I think I will leave it as is unless my fish shows sign of illness. I can always gradually lower it over the course of a few days to the hypo point.

And I am glad you guys let me know about antibiotics. I was about to buy them too. Saves me some dough...

Thanks for the help!!

:)

[ATJ]

Originally posted by Biggen
Ok. So bony fish are pretty well adapted to running at lower salinity.
I think it is safer to say that ay least some bony fish are able to cope with lower salinity. I am only aware of one study into a reef species. Woo and Chung (1995) found that emperor angelfish could survive without any problems at all down to 7 ppt and were physiologically euryhaline. Their bodies had adjusted to that salinity just as any estuarine fish would.

I also have not found any fish that appeared to have any problems with hyposalinity, but that is just anecdotal.

Woo N.Y.S. and Chung K.C. 1995. Tolerance of <i>Pomacanthus imperator</i> to hypoosmotic salinities: changes in body composition and hepatic enzyme activities. <i>Journal of Fish Biology</i>.<b>47(1)</b>:70-81.