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Levamisole hydrochloride, shrimp and water clarity

Home Forums Fresh and Brackish Water Fishes Levamisole hydrochloride, shrimp and water clarity

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    Hi all,

    Bit of a funny one this, I’ll try not to make it too convoluted.

    Backstory; I had recently noticed that a couple of my older female rosy loaches had lost a lot of weight and were beginning to develop a hunched appearance. This isn’t something I’ve seen before, and my first thought was that it might be some sort of internal gut parasite such as the dreaded Camallanus 

    I don’t normally rush to medicate my tanks, but as the weight loss continued I decided to try dosing levamisole hydrochloride (‘Harka Verm’ 8% oral solution). I dosed last night before turning off the lights and went to bed.

    Firstly an observation regarding shrimp; this is generally touted as safe for inverts and indeed, it hasn’t directly killed any of my shrimp. However, they definitely don’t like it. This morning all the shrimp (RCS and Caridinia simoni simoni) were acting ‘groggy’, disoriented and sluggish. Additionally, overnight at least 20 individuals had jumped out of the tank and were dried up on the floor. A large water change later and the remainder are starting to perk up. So, it may not be immediately lethal to shrimp, but they sure don’t like it.

    Second observation; I have had a long term issue with water clarity since re-doing my soil substrate last year. I had put this down to forgetting to wash the grit that I mixed in with the soil, and stay on top of it by running a 1-micron cloth filter bag inline with my main filter. Having done some rescaping earlier in the week I still had some considerable residual cloudiness that was taking a while to clear. However, as well as shrimp all over the floor, this morning I was also greeted by absolutely gin-clear water.

    Any ideas how the Harka Verm might have helped clear the water, and any thoughts on my loach health – obviously it’s too early to tell if the treatment has had much effect?





    check your tank for ammonia and perhaps for nitrites as well.

    (yes, I know that levaimisole is not supposed to have an effect on the biofilter, just like it is supposed to have no effect on the fish, but I know of a couple of cases when levamisole treatment resulted in high ammonia levels almost right away. This would explain your shrimp behavior. I don’t know the mechanism — perhaps the impurities in the med — but all known problem cases came from hard-water areas.)

    2ndly, guessing Camallanus without actually seeing the worm is a leap. It may not be a worm at all, but if it is a worm, capillaria is more likely (Camallanus is large enough to kill small loaches outright rather than cause them progressively lose weight.) And Levamisole does not have any effect on most strains of cap. Use flubendazole instead which is wide-spectrum against internal parasites and does not seem to cause strange effects.

    caveat 1: I don’t know what flubendazole does to shrimp…I’ve been told it is safe, but this is a hearsay.

    caveat 2: what you describe may have other causes, including bacterial or protozoan, the latter being the most common ime. Still flubendazole makes sense as a start. (My own approach to problems like you describe is massive anti-protozoan treatment first.)

    One way to make the right decision is to look at the history of the tank. If you had it running for 6 months with nothing new added and your food being safe, it is not worms of any kind.




    I’m a big fan of flubendazole and I have used it with cherry & amano shrimp in the tank with no ill effects. It is a bugger to dissolve and it will, at least temporarily, cloud your water. I like to use it in a q-tank with no substrate or other organic matter. Not sure how it would go in a heavily planted tank?

    Don’t rosy loaches naturally have a bit of a hunch when they mature?



    Hi guys, thanks for the feedback. I also have flubendazole from when I treated a hydra outbreak a while back and was planning on using that after finishing the levamisole treatment in order to cover my bases. 

    mikev, I did add a second batch of rosy loaches 4 or 5 months ago, so it is possible that something may have come in with them, although those individuals all appear healthy.

    plaamoo, the older loaches do have a slight hunch, but its far more accentuated on the two that appear unwell, and they also show noticeable wastage and lethargy. The females are generally quite shy so I don’t see them that often in the big tank, so it was pretty noticeable when they started dropping weight between sightings.



    4-5 months is too long for internal parasites incubation, so the chances are that flubendazole will not do anything. If the situation continues getting worse after a few days, I’d go for quinine.



    @mikev said:
    4-5 months is too long for internal parasites incubation, so the chances are that flubendazole will not do anything. If the situation continues getting worse after a few days, I’d go for quinine.

    OK. Havne’t come across quinine before as a fish med. What form do you buy it in? Just had a quick google and it seems its only really available as quinine sulphate here, which you can only get with a doctor’s prescription in the UK. 



    I use quinine sulphate. No prescription is needed in the US and since this is not an antibiotic, you can probably buy from the US (or have someone mail it to you).

    A very good thing to have around, it is also the only med to deal with resistant Ich (and the best med to deal with any Ich).

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