Freshwater dip


Awesome Dude
Would a freshwater dip elliminate Ich from a pair of clowns? if yes then what is the recommended time to leave them in there?
No, a Freshwater Dip will not dislodge very much, if any, of the Crypto from your fish. You will have to utilize a full treatment of either Hypo or Copper to have the fish truly "Ich Free".
From wetwebmedia

"I highly recommend performing a freshwater dip on each fish before being placed in the treatment tank. The freshwater should be properly buffered and heated to the same temperature as the tank that your fishes have been residing in. Use of a non-toxic anti-bacterial agent, such as Methylene Blue, is encouraged during the dip. Use enough Methylene Blue to color the water a deep blue. The duration of the dip should be from 3 to 5 minutes, depending on the tolerance of the individual fish(es) being dipped. Keep a close eye on the fish during the dip process, and be prepared to remove them to the treatment tank quickly, should they show extreme distress during this process. The freshwater dip is a standard part of the acclimation and quarantine process at most public aquariums throughout the world, and is an effective procedure that can reduce or eliminate many external parasites, including Cryptocaryon. The reason that freshwater dips are so successful is that the parasites simply cannot make the osmotic "stretch" to freshwater as well as the fish can."

By Scott Fellman

So, if they are sick, this will not cure them, but will eliminate some of the cysts. read this for more info:

The bottom line becomes clear when you familiarize yourself with the lifecycle of the parasyte: Cyst on fish, free swimming, single cell tomont which settles somewhere on the aquarium, and free swimming protozoans called theronts.. If you just take the fish out and dip it, the parasite is still in your tank. Besides, the stress of catching the fish and the dip makes them weaker.
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"Are freshwater dips effective?

Freshwater dips are generally ineffective in the treatment of marine "Ich" infestations. Trophonts burrow deeply into the epithelium where they are generally protected from external influences. Colorni (1985) found that even after 18 hours in freshwater, infected fish still have trophonts attached in the same positions as they had held before the freshwater treatment. The trophonts later detached and completed their life cycle as normal.

Trophonts penetrate the epithelium which causes a loss in osmoregulatory capability. Infected fish are less able to cope with a sudden and drastic change in the ionic concentration of their environment. This is likely to cause further stress to the fish which will impair their ability to acquire immunity to the parasite."
From ATJ

"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."
From Steve Pro

"Freshwater dips

Freshwater dips are largely ineffective in the treatment of Cryptocaryon irritans (Burgess, 1992). The host epidermis and thick layer of mucus form a barrier impervious to osmotic shock (Colorni, 1985). "Most of the trophonts whose hosts had undergone hyposalinity treatment, including freshwater, for at least 18 h, were still alive and occupied the same position in the host by the end of the experiment, following re-adaptation to sea water. They later dropped from the fish, encysted, and the tomonts produced tomites" (Colorni, 1985).

Note that the above quote says "most" and not all trophonts. Trophonts embed themselves completely into the epithelium under a layer of skin. This protects these trophonts from dips. As the trophonts grow in size they gradually displace the overlying epithelium. This is when they become visible as white spots or nodules. Exposed trophonts may be susceptible to freshwater dips, but trophonts that survive continue in their life cycle making this method only partially effective at best.

"Freshwater dips can cause osmotic shock. Typically the fish are exposed to the air during the process of capture, handling and transfer, all of which are stressful to the fish. Freshwater dips cannot be depended on as the sole method of treatment for Cryptocaryon irritans and can be counterproductive because they are highly stressful to the fish. They should only be used in combination with other treatments that will successfully interrupt the parasite's life cycle."
From TerryB
Intersting stuff, specially the Burgess study.

I also find it interesting how the experts can have such different views. Thanks