# Levamisole hydrochloride, shrimp and water clarity



## BigTom (17 Jun 2013)

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?

Cheers,
Tom


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## DrRob (17 Jun 2013)

Levimasole is a known neurological excitement agent, so I can imagine shrimp getting jumpy on it, given their less well protected nervous systems.

Otherwise, it may have killed some microfauna that were responsible for the clouding.

Final thought is that there may be something simple in there like EDTA that may have triggered a precipitation of any  free floating stuff.


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## BigTom (17 Jun 2013)

DrRob said:


> Levimasole is a known neurological excitement agent, so I can imagine shrimp getting jumpy on it, given their less well protected nervous systems.
> 
> Otherwise, it may have killed some microfauna that were responsible for the clouding.
> 
> Final thought is that there may be something simple in there like EDTA that may have triggered a precipitation of any free floating stuff.


 

Hi Rob,

Looks like we're thinking along similar lines. Bacterial clouding and/or some sort of chelation/precipitation agent were my first two thoughts as well. Sadly the Harka Verm doesn't list any ingredients except the levisamole hydrochloride.


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## Yo-han (17 Jun 2013)

What concentration did you use in your tank? 2 mg/L is all it needs for camallanus. It is not more effective in higher dosages, but will become increasingly toxic for invertebrates (and all other animals with loaches like kuhlii's being the first to respond. I used it in my tank against camallanus and did not loose one shrimp. The kuhllis seemed more sensitive than my shrimp, swimming around very actively for a few hours. Make sure you vacuum the gravel very well 24 hour after adding the levamisole to remove any paralysed worms.

Second, one treatment is absolutely useless (don't ask how I know ) You need to repeat the treatment after 14 days, because otherwise the eggs survive and become new worms. Best to treat it 14 days later for a 3th time.


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## BigTom (17 Jun 2013)

Yo-han said:


> What concentration did you use in your tank? 2 mg/L is all it needs for camallanus. It is not more effective in higher dosages, but will become increasingly toxic for invertebrates (and all other animals with loaches like kuhlii's being the first to respond. I used it in my tank against camallanus and did not loose one shrimp. The kuhllis seemed more sensitive than my shrimp, swimming around very actively for a few hours. Make sure you vacuum the gravel very well 24 hour after adding the levamisole to remove any paralysed worms.
> 
> Second, one treatment is absolutely useless (don't ask how I know ) You need to repeat the treatment after 14 days, because otherwise the eggs survive and become new worms. Best to treat it 14 days later for a 3th time.


 

Hi Yo-han.

I dosed 13 mg/L, which I'd seen recommended on a couple of places. I see now that other sites recommend 2 mg/L, so it was probably a heavier dose than it should have been, to be fair.


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## Yo-han (17 Jun 2013)

Yes it is! Most fish can handle over 200 mg/L, but loaches and shrimp are more sensitive. 3x 2 mg/L 14 days apart got rid of my camallanus (unfortunately already lost all my dwarf cichlids and some other fish before I knew what it was). There is a very good article on loaches.com


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## Michael W (17 Jun 2013)

The symptoms also fit fish TB _ Mycobacterium Marinum._


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