# My Experience with Fenbendazole for Killing Hydra/Planaria in CRS/CBS Tank (Update)



## ngo911

Just thought I'd share my experience with Fenbendazole so that others may learn from my mistakes.

The Fenbendazole definitely killed all the hydra and planaria in my tank. Unfortunately, it has also killed some of my shrimp.

Going against the advice of the person who gave me the Fenbendazole, I decided to dose at 1ml/10gal, which is recommended by many. So for the first dose, I put 2 ml in my 22gal tank. I saw no ill effects on the shrimp and they were eating as normal. The hydra also began to shrink and die.

Seeing as how well everything went the first time, I dosed another 2ml 48 hours later, which is also recommended as a follow-up treatment, to ensure all the hydra/planaria are killed. Unfortunately, this time, all the shrimp stopped eating and were less active, and by the next morning, 5 shrimp were dead. Two more died shortly after.

Seven deaths may not seem like much, but considering I only had 20 to start with, that is a little over 33% death rate. Imagine if I had a huge colony! I suspect there will be more deaths when its all said and done, because they are not eating at the moment.

Anyways, to make a long story short, Fenbendazole does and will kill hydra/planaria, but I would recommend either going with 1ml/10gal for the first dose and 0.5ml/10gal for the second dose, OR play it extra safe and go with 0.5ml/10gal for both doses.

Good luck!


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## effox

Are water changes recommended between dosing?


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## Captured Moments

On 2 occasions I used "Mebendazole" to rid of planaria and hydra. Same kind of stuff as Fenbendazole.. dog dewormer.. Dosage similar. Works pretty quick on planaria which dissapear after 1 day. Hydra is a bit more persistent and will take longer about 2-3 days. I didn't dose a second time.. just make sure you do a thorought water change after a few days to rid of remaining trace in the water otherwise it will affect snails (kill them) and affect health of your fish as well.


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## ngo911

I didn't read anything about water changes in between doses, but perhaps I should have. The water did clear at the end of the second day, so I thought maybe the meds were inactive after the water cleared up before the second dose.

Maybe I could have also skipped the second dose altogether too...


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## effox

I used No Planaria from Patrick, I don't know if its got the same base checmicals in it or not, but it didn't kill the shrimp when I used it anyways.


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## Dosan

Sorry to hear about the losses. Hope they start eating soon.


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## CRS Fan

effox said:


> I used No Planaria from Patrick, I don't know if its got the same base checmicals in it or not, but it didn't kill the shrimp when I used it anyways.


No Planaria is a palm oil extract.


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## CRS Fan

ngo911 said:


> I didn't read anything about water changes in between doses, but perhaps I should have. The water did clear at the end of the second day, so I thought maybe the meds were inactive after the water cleared up before the second dose.
> 
> Maybe I could have also skipped the second dose altogether too...


If you had a large population of planaria or hydra that died within the first 24 hours, you may have had a slight ammonia spike as a result. If your shrimp were CRS, they tend to die extremely quickly if any ammonia is present at all.

I've used the liquid Panacur (Fenbendazole in aqueous solution) 5 times with a second does 48 hours apart for each does (at 1ml/10 gallons) with no losses. These were in tanks that included populations of Tigers, Cardinals (yes Sulawesis at one time), CRS/CBS, Blue Pearl, and Painted Fire Reds. Mind you.... I overfilter all my tanks and they are all planted.

JMHO.

Stuart


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## ngo911

Stuart, that is very plausible in my case, since I am not over-filtrating (only 3 sponge filters). I hadn't even thought about that.

I am testing all parameters right now, but even if they are all good, I could have still had a mini spike that has all settled down now.

I will also do a 25% water change right after.

The funny thing is that a baby shrimp shrimp survived as well as 3 out of 4 berried shrimp. I would have thought that they would be the most susceptible ones.


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## ngo911

Parameters were all good.

They were immediately more active after the water change so hopefully thats the end of the deaths.


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## ngo911

So just an update, there are 2 shrimp left. Not sure if they will make it. This makes me think its not an ammonia spike that killed them since it has been a week since first treatment, and the tank was tested a few days earlier and the parameters were good.

So again, I either should have dosed less, or did a water change in between doses. It really seems like the follow-up dose hurt the most, as there were no symptoms at all after the first.

No more hydra or planaria though! T_T


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## ngo911

Oh and the setup will be up for sale soon... so if missed out on one of Charles' super long 22g tanks, keep an eye out for this one!


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## 1mad1

hi, i'v just joined this site, i have 2 large tanks with a variety of fish but after a long hard search have discovered i have hydra. i'v been given some liquid pancur(fenbendazole) u said ur dose rate is 1ml per 10g but what strength was ur fenbendazole as it comes in a few concerntrations?


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