Hyposalinity for treating Cryptocaryon Irritans (Marine Ich)

Discussion in 'Fish Disease Treatment and Diagnosis' started by aykwm, Jul 2, 2017.

  1. aykwm

    aykwm Research Addict! R2R Supporter Build Thread Contributor

    Jun 2, 2017
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    This is my first article on this forum so I hope you enjoy it and benefit from it.

    One of the most common diseases in saltwater that we usually face is Cryptocaryon Irritans or commonly known as Marine Ich. There are few treatments that pop to mind, Copper, Chloroquine phosphate (CP), Tank Transfer Method (TTM), or Hyposalinity.

    Hyposalinity was always somewhere there on the list, some say it works, some say they had no success with it, so I decided to do some research to find a solution once and for all, does it work or no. Note that Hyposalinity is claimed to work only on marine ich and not any other type of parasites. So if you have velvet, fluke, brook, etc.. use the appropriate treatment and totally forget about hypo.

    Spoiler Alert: It does not work (I know some people will disagree, but hey experiments proved it, and also you might be lucky to not have the resistant strain), use one of the guaranteed methods to treat ich: Copper, CP, TTM. Always observe fish for few weeks after treatment before placing in Display Tank. Hypo is still beneficial for fish and you can run tank on it (FO/FOWLR or QT only) although not to extreme ranges, will do an article soon about that :D.

    Introduction to hyposalinity treatment:
    From the name you probably guessed what is meant by hyposalinity treatment, or hypo for short. Basically, you want to treat the fish by lowering the salinity to extreme values where fish can still survive it but parasites won't. Its not clear at which salinity it’s stressful for fish or start affecting it, but people commonly run it at 1.008-1.013 (11-17 ppm).

    So how does it work?

    Hypo will only work on ich (and not all strains of ich). Unlike fish, the Crypto. are not capable of osmoregulatory, that means that as salinity drops, fish will adjust and balance the salts in their bodies so they don’t swell up, but the crypto cant, so hyposalinity will cause them to absorb the surrounding water to a point where they will pop and die, that’s why its necessary to lower the salinity enough to allow the parasite to absorb as much water as possible to make this happen.

    That makes sense, so why it isn’t an effective treatment? Low salinity will cause the parasite to swell and pop, problem solved, correct?

    Well, in most cases it will work, but as you know Ich has many strains, unfortunately, some are capable of swelling up and not popping at these ranges, they will still be able to reproduce and continue the life cycle normally. This study shows that fish were collected from fish farm infested with ich. The study utilized hypo and hyper as a method of treatment. I suggest you read it as it has some useful information, but here is what they found. They tested fish with different ranges of salinity and they found out that ich can survive at salinity of 15 ppm (1.011) but didn’t survive the 10 ppm (1.007) sality solution. So, somewhere in between is the sweet spot for killing ich right? Regrettably, no. Other than the fact that this is not a safe zone to place the fish at, another more recent study found out that crypto can survive even lower salinity levels. If you read this study you will found out that ich can survive salinity levels as low as 5 ppm (1.004). You definitely don’t want your fish to be exposed to this low level of salinity as it will most likely die. Note that this is Crypto. (Marine Ich), not to be confused with Ichthyophthirius multifiliis (Freshwater ich). This is another article that explains the recent study and is a good read overall.

    Full article here.

    You can also google hypo treatment failing, believe me you will find a lot of topics where people tried hypo and ich pops back again.

    Ok, so hypo is not effective treatment, but many people had success with it how?

    They might be lucky and had the strains that died at the hypo levels they had. Crypto. has a lot of strains, and each strain has resistance against a parameter or two. Similar to the strain that can survive 76 days in fallow tank, another strain can survive at lower salinity, it's simply evolution taking its course. Another possibility is that it is ich management instead of ich eradication. Ill be adding another topic soon about the benefits of hypo, but basically it can boost immunity and decrease stress, so no ich is visible.

    So this concludes the hypo treatment. As you know hyposalinity is not 100% effective against ich, it is better to treat with other more effective methods like copper, CP, or TTM. Ich has been found at salinity levels as low as 5 ppm, making it impossible to treat with hyposalinity. Ill be posting soon another thread about benefits of hypo, after all it might be beneficial, and not only for ich but probably for other diseases too.

    Hope you enjoyed the thread and learned something, and happy reefing :D
    Last edited: Jul 2, 2017
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  2. Humblefish

    Humblefish Dr. Fish Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Louisiana Reef Club Expert Contributor

    Nov 9, 2014
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    Thank you for this! :)
    aykwm likes this.
  3. Maritimer

    Maritimer Moderator Staff Member Team R2R R2R Supporter CTARS Member R2R Excellence Award Partner Member 2019 Build Thread Contributor

    Nov 21, 2015
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    SouthWestern Connecticut
    Thank you, Aykwm - very clear, concise ... and convincing! Terrific work!

    aykwm and Humblefish like this.
  4. somebloke

    somebloke Member

    Dec 7, 2016
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    Have the results of the Yambot study been replicated in lab conditions? I'm genuinely curious.

    I'm in the middle of an attempt at hyposalinity treatment of three fish in a single hospital tank at 11.2 ppt.

    Something interesting I've noticed when measuring with three refractometers (one of which consisted of me bringing a water sample to my LFS). After calibration of all three at 35 ppt, they varied significantly at salinities near 11 ppt. They had more parity when they had been calibrated at 0 ppt, but not much. This leads me to wonder whether the refractometers in common use are accurate in mid-ranges when calibrated at the practical extremes of 0 ppt or 35 ppt. If not, this would obviously contribute to disparity of result between hobbyists.

    At any rate - I'm using a meter that calculates salinity from conductivity. I'm resetting the water to 11.2 ppt twice a day. I don't have an automatic topoff system so it increases in between, but not beyond a reading of 11.3.

    What would be helpful is a reference solution proximate to 11.5 ppt. One that hobbyists can buy on Amazon and don't have to special-order from scientific materials suppliers. :)
    Last edited: Dec 31, 2017
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