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Oceangirl
09/20/2005, 10:33 PM
Hi Steve,

I read an articlel you wrote about quarantining fish. You mentioned to perform a freshwater dip on all new arrivals.

I'm ordering fish from the internet so its safe to say that when the fish arrive the pH will have dropped a good amount, because of this I acclimate the fish for 2 hours.

My questions are (if you don't mind):
1. Is it safe for the fish to go through a freshwater dip after the 2 hour acclimation period?

2. Do I have to add any type of medication to the freshwater dip?

3. What would be the proper way to perform a freshwater dip?

Thank you very much for your time,

Mel

Steven Pro
09/21/2005, 06:53 AM
Here is a portion of my article on Marine Ich that deals with freshwater dips:

Freshwater dips are a highly effective form of treatment against a wide variety of parasites, although their use against Cryptocaryon irritans has been questioned (Colorni, 1985). I am including them here because I still choose to employ them, as I believe they have at least some effect against Ich and because they have been proven effective against Amyloodinium, Turbellarian Worms (the so-called Black Ich), some Flukes (Noga, 2000), and Uronema (Kollman, 2003). For these reasons, freshwater dips are still part of my standard operating procedure when receiving fish.

For some reason, many hobbyists are extremely reluctant and nervous about freshwater dipping their fish, yet show little concern about using toxins, poisons, and carcinogens, such as Copper or Formalin, for treatment. It is my contention that any fish that does not survive a properly conducted freshwater dip would not have lived regardless of treatment. I have dipped hundreds, perhaps thousands of fish, and have yet to kill a fish with a freshwater dip. I define this by the fish dying either in the dip bucket or within hours of the freshwater treatment. If a fish dies a day or two later, while one may claim it was the result of the dip, it is more likely that the disease was too far along and the fish too damaged to survive.

To prepare a proper freshwater dip, take either dechlorinated tap water or demineralized water (RO or DI), aerate for an hour to maximize dissolved oxygen, heat to match the temperature of the dip water to that of the tank water, and then add buffering compounds to match the freshwater pH to your saltwater pH. The aeration should continue throughout the dip. It is crucial to match temperature and pH and to maximize dissolved oxygen. Most people that experience problems with freshwater dipping have made an error in these critical parameters.

The recommended duration of the dip varies from author to author because different species of marine fish tolerate freshwater to different degrees. Generally speaking, any dip less than two minutes is useless. Many fish will easily tolerate five, ten, even fifteen minutes or more. The least tolerant fish are wrasses, lionfish, pufferfish, drumfish, hi-hats, jackknives, firefish and many of the scaleless fish as a rule (Calfo, pers. comm.). I also choose not to dip lionfish, foxfaces, or any other venomous fishes because I don't want a flying torpedo of spines to come shooting out of a dip bucket at me. A lionfish has stung me before, and it is not an experience I ever wish to relive.

Please only dip one fish in each bucket. If you must dip several fish, it is best to make up several smaller freshwater dips versus one large bucket, and always discard all dip water. I also would like to warn you about dipping fish that excrete toxins. There are several fish that give off toxins with their protective slime coat. Mandarins, boxfish, and the Six-line Grouper are a few. When in freshwater, they will naturally excrete more protective slime. There is a possibility that in the confines of a dip bucket, these fish could poison themselves or others, so be careful.

The best advice I can give you is to observe your fish closely. Some fish will swim around like nothing is happening. Others will go straight to the bottom and lie there. Definitive signs of trouble are manifested by the fish jumping out of the dip bucket and spitting water.

There is an alternative to standard freshwater dips that should also be mentioned. Some individuals prefer to use freshwater with methylene blue in the dip (Fenner, pers. comm.- more information here). Methylene blue is an anti-microbial dye. It is effective against a wide range of microbes such as bacteria, fungus, yeast, etc. This combination works well to rid the animal of external parasites and provides some protection against secondary infections. As I stated in part one of this series, I almost always use daily water changes. These daily cleanings tend to spur the fishes' own immune system to combat any secondary infections by helping to maintain optimum water quality, so I have not felt the need for using Methylene blue, but it is a worthwhile option to consider.

I wanted to add a footnote on the effectiveness, or lack thereof, for freshwater dips against Cryptocaryon irritans. The question of whether they work or not stems from one study, Colorni 1985. In that study, Colorni watched as trophonts and their host, the Gilt-Head Sea Bream, Sparus aurata, were given freshwater dips. After the dips, which lasted up to 18 hours, were administered the trophonts were still there in their same positions. These same trophonts later dropped off the fish and reproduced successfully. My first comment is, I am unsure if any of the common ornamentals we see in the trade could withstand an 18-hour freshwater dip! Secondly, Gilt-Head Sea Bream, Sparus aurata, are found in marine, brackish, and even freshwater environments. I am concerned that whatever protection these fish have that allows them to withstand such osmotic shock could also unintentionally protect the parasite. Please take my musing with a grain of salt. Better yet, make that a whole 50-gallon bag. I am not a doctor, nor am I schooled in fish pathology. This was merely something that struck me in my reading, so I wanted to mention it. In fact, it has aroused such curiousity that I am currently working on developing a protocol for testing freshwater dips against Cryptocaryon irritans in a common marine ornamental species. I will keep you posted.

With all that I have discussed concerning freshwater dips my position on its use may seem a bit murky. Just to clarify, I do employ and advocate the use of freshwater dips when first receiving fish. I believe all fish that can be dipped should be administered this treatment prior to placement into a proper quarantine tank. This is done in an effort to minimize all possible parasitic infections. I do not, however, recommend freshwater dips as a cure for Cryptocaryon irritans. In my opinion, the repeated handling and osmotic shock of repeated dips are far too stressful to warrant its usage when other proven, but less aggressive treatments are available such as hyposalinity or daily water changes. Lastly, assuming freshwater dips can kill the embedded trophonts on a fish, once they are returned to the infected aquarium, they are just going to contract this pathogen again. So, I recommend using them and using them once only upon receiving the fish to minimize all possible parasitic infections.

Steven Pro
09/21/2005, 06:59 AM
Now, the main question is whether or not you want to FW dip a fish that you receive from an internet or mail-order place. There is no hard and fast rule. As a hobbyist, I would prefer not to subject a fish that has been in transit for an extended period of time to a FW dip. Fish I bring home from a LFS do get a dip. And, as a LFS employee, we would FW dip everything. It is a matter of the lesser of two evils. Would so of the fish at the shop die a day or two later from all the stress they had endured? Yes. But, were most of the fish able to handle it and were relatively free from disease? Yes. In those situations, it is a matter of saving the most fish possible at the possible expense of a few. If the fish looks good, is not rapidly breathing, and is a species known for infestation, I would probably dip it. Otherwise, they should go straight into QT ASAP.

Oceangirl
09/21/2005, 01:19 PM
well said steven, Thank you