Guide to Planaria and Hydra Elimination

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Planaria and Hydra Elimination – 

Planaria and Hydra are common pests, and both are a result of poor tank care. Hydra are dangerous, and Planaria are unsightly. My shrimplets at the time were in danger of being stung and killed by the Hydra, so I took action.

This article is based off of a compilation of information along the web on the elimination of Hydra and Planaria using the common dog dewormer Panacur-C. Use this method at your own risk! No method is perfect, but the way I used it with fragile animals such as shrimp, it will be safe for most anything. I used the lowest possible dose that was effective, and it worked quite well.

Here is the method I used, let me know how it worked for you!

To those newbies who don’t know, I’ll give you a definition of Planaria and Hydra.

Small worm creatures with a spade shaped head, very flat, rarely exceeding 3/4 of an inch. They are milky-white in color, and are the #1 pest of the shrimpers world, tied only with Hydra for their position. They are harmless, which is why I would understand if some feel no danger. They are usually caused by dirty substrate and overfeeding, a common trait of new shrimp keepers.

 This is not my picture. I give all credit to the original photographer.

This is a general photo of a Planaria. All Planaria shape/color does vary, but this is a general description of the creature. This is not my picture. I give all credit to the original photographer.

Small, 1/4″ white creatures, in the same family of corals. They look like a coral, only in miniscule size. Also like corals, they have a biting sting to small organisms, capable of killing and eating baby shrimp and fish fry. Do not confuse this creature for the Detritus worm!


This is a hydra. There may be slight differences in their appearance.This is not my picture. I give all credit to the original photographer.

These pests together are even worse, for you get dangerous and ugly at the same time. In general, you should do your best to get rid of either (Or both) of these pests as soon as possible!

Panacur-C is just the brand name for a common dog dewormer (Can be found online [eBay, Amazon, individual sellers], and at large chain pet stores [Petsmart for example]) for the chemical Fenbendazole. This is a chemical that attacks and eliminates intestinal parasites. Perhaps some agree that it is strange that a dog dewormer can be used in aquariums. No matter what its original purpose was, and still is, its effectiveness was evident to me.

Here’s the process of making the Fenbendazole solution and using it:

1. Positively identify hydra and/or planaria in the tank. It does not matter how many there are.

2. Purchase the Panacur-C package containing three 1-gram packets.

3. When it arrives, rinse an empty water bottle (Or other tightly sealing container) with water, and then fill it with 200 mL of either RO/distilled or dechlorinated tap water.

4. Tear open the packet, and pour the contents not into the water, but into a baggie. Using a rolling pin or some other broad, heavy object, crush the Fenbendazole granules into a POWDER.

5. Pour the powderized Fenbendazole into the water you prepared in the water bottle (Or other container with the above specifications).

6. This step is one of the most important of all. Shake the Fenbendazole in the water until your arms hurt. There may not be total dissolvation, but do your best! Warm water will most likely aid in this process.

7. Measure out 20 mL per 10 gallons of tank water. Squirt at all visible Planaria/Hydra, then inject the remaining amount of the dose into the substrate. This is not required, but I do think it helped evenly distribute the Fenbenazole.

8. Wait a few hours, overnight is best. This will give time for the Fenbendazole to take effect.

9. Even if the pests are all dead, dose again every 24 hours for a few more days.

10. Enjoy pest free tanks!

I am no expert at killing these pests, but I thought the knowledge I have with them could be found to work effectively and quickly with others, a cheap, safe, and potent method of pest elimination.

Prevention tips are:

1. Feed sparingly. This is the number one cause for infestations. Uneaten food is food for pests like Planaria and Hydra.

2. Clean your tank thoroughly. A gravel vacuum should be thoroughly used, don’t forget it!

3. Do your homework on these pests! Don’t only look back at this article, this has no where near all the info. Read up on these guys, this will definitely help you prevent these pests if you are serious about keeping them away.

4. Don’t be careless! I was careless, and I payed for it. Keep and eye out for pests, and be quick to fix the issue.


Thanks for reading!

Links to other’s pictures: (Hydra Picture) (Planaria Picture)

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