How To Get Rid Of Hydra In Shrimp Tank?

How To Get Rid Of Hydra In Shrimp Tank

Hydra, one of the unwanted guests in your freshwater shrimp tank that can be a real danger for both your baby and adult shrimps. Although it is inevitable that they will sneak into your tank while adding plants or shrimps, there are a handful of effective methods of how you can get rid of hydra to give your shrimps a risk-free life.

You can get rid of hydra from shrimp tank by removing manually or siphoning them out. Applying a natural product containing herb extract like Planaria Zero/No Planaria, Sea salt, etc can also be useful. Fenbendazole, H2O2, Potassium Permanganate, and Copper Sulfate are also commonly used chemicals to destroy hydra.

There are other technical options like controlling food sources, using light, very high and low temperatures, or adding predator fishes or snails. In this article, I will discuss some useful methods of how you can get rid of hydra in your shrimp tank and their shortcomings and side-effects so that you can choose the best way by considering the pros and cons.

And if you are a new shrimp keeper, scroll down to the end of the article to know more about hydra and how to prevent it from entering your aquarium.

What Is Hydra?

Hydra is a jellyfish-like creature that is too small to notice. Their tubular body has a sticky base with which they cling to the surface and on the opposite side, there are stinging tentacles that they use to attack the prey.

Unlike most cnidarians, they like to live in freshwater. They reproduce asexually by producing buds that result in new Hydras within a short time. Like the nine-headed fierce mythical beast Hydra, it can re-grow if its body if separated in any way.

Which Animals Can Hydra Attack?

Although it is just an inch or less, Hydra can attack and kill small fishes double of its own size.

Hydras feed on daphnia, cyclops, small aquatic crustaceans, and other freshwater organisms. However, fry, baby shrimp, and other small fishes are their favorite meal and they kill them with their stinging toxic tentacles causing a heavy blow.

They will attack and eat only the small fishes. Larger fishes will not even feel their blow.

Why Hydra Is Dangerous For Your Shrimps?

You have already read that Daphnia, Cyclops, and other freshwater organisms and copepods are Hydra’s favorite foods.

Daphnia, are usually 0.2–5 millimeters in length while a 14 days baby shrimp is 4 or 5 mm in length. So, hydra can easily gobble a 14 days old baby shrimp. Actually, if you have less than 1-month-old shrimps in your tanks they are in potential danger from the hydra.

How To Get Rid Of Hydra In A Shrimp Tank?

So, worried about hydra infestation in your shrimp tank? These are some proven ways to destroy the hydra colony effectively.

1. Taking Out Manually

Taking Out hydra Manually

When hydras clinch on the glass of your shrimp tank, you can easily remove them manually.

Never squash it with your nail! You can simply grab them and take out of your tank when there is a small number of hydras.

They tend to flinch and curl into a ball when some threat occurs. So, if you touch them, they will not hurt your hand.

If you do not want to touch them, with a sponge wipe your glass making sure that you do not separate their bodies in any way and leave any pieces in your tank. Otherwise, one hydra will regenerate and result in two separate hydras.

  • Manual removal is only applicable when a limited hydra infestation occurs on a smooth surface. On uneven surfaces like plants or rocks, you have to opt for another option.
  • If the hydras have established their territory on your tank already, then you should go for chemical removal.
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2.  Planaria Zero or No Planaria

Planaria Zero is a shrimp-friendly product for removing the hydra colony from your tank. The name suggests that it is for Planaria but it also kills hydra effectively within a few days.

The magic ingredient of this product is betel nut extract that kills hydras naturally without harming your shrimps. Moreover, it is safer than the other chemical methods I’ll mention below.

Dosage of Planaria Zero

         Day        Usage
         1st1 spoon/6 gallon water
         3rd1 spoon/6 gallon water
         4th20% water change
        10th1 spoon/6 gallon water
        11th20% water change

With the included spoon add the powder directly to your water when it has enough surface agitation. You do not have to complete the full dosage if you are lucky and may get the result after the first dosage.

Remove any carbon filters or synthetic filter resin before adding it as these will remove the Planaria Zero from your tank water. Also, remove your pet snails as this powder may prove lethal to them.

Put your carbon filter again to remove any possible trace of Planaria Zero from your tank.

No planaria is another bio-degradable and a safe product like Planaria Zero which is also extracted from herbs and works within three days.

3. Adding Predator Fishes Into The Tank

Adding Predator Fishes Into The Tank for removing hydra

Blue Gouramis, Sparkling gouramis, Mollies, Paradise fish are good predators for your hydra colony. These hungry fishes will hunt on the hydras on their own costing no effort from your part. So, you can engage these fishes to drive out your invisible guests completely.

  • Once the hydra colony leaves your tank, you have to do something about this fish. You have to take them out from your tank if you don’t want to disturb your shrimp colony. Because even smaller fishes than these can put an end to your shrimp colony.

4. Controlling Feeding Sources In The Tank

Live foods are popular among the shrimp keepers for conditioning the shrimps for breeding, and to ensure proper nutritional balance. But, in many cases live foods are collected directly from freshwater ponds and streams which can potentially introduce hydra to your tank.

Moreover, hydra lives on consuming small living creatures. So, when you are feeding your shrimps living food like daphnia, you are also inviting the hydra for a healthy meal. Overfeeding helps to increase their colonies while target feedings can help to keep the Hydra population controlled. 

You can use feeding dishes for your shrimps to control the feeding sources in your tank thus try to starve hydra out. When you cut back the food, they will lose stability on their foothold. This is not an instant solution and needs a few weeks to show the result.

5. Adding Snails To The Tank

Adding Snails To The Tank

The common Pond snails, Asolene spixi snails, Marisa cornuarietis, etc. are some species that will seek out and gobble the hydras in your tank.

These snails’ aim is not hunting down the Hydras for you. They just gobble anything to fill their belly. The species, Marisa Cornuarietis, will also eat some plants so take care of this fact too if you have plants in your tank.

Most freshwater snails voluntarily consume waste products. Luckily, these are the food for small microscopic organisms while the small organisms are a food source to the Hydra. So, these snails will also reduce the food source of hydra besides eating them.

6. High And Low Temperature

Hydra cannot live up to high and low temperatures. So, you can opt for this option and use a heater to get rid of them.

Make sure you remove all the shrimps from the tank. Continue 105 – 110 degrees Fahrenheit (41-43 degree C) temperature for several hours.

As you won’t continue this heat for long, your plants do not have any problem with this treatment. Moreover, the heat is not enough to cause any harm to most of the plants. But, in case of any sensitive plant, remove them out and keep in another water container. 

You should also remove artificial plants and rocks infested with Hydras and soak them in a 10 percent bleach solution for about 15 minutes. Scrub and rinse with water and air dry before placing it in the tank.

Then turn the heat down and vacuum the gravels to get rid of any possible Hydras at the bottom of your tank.

Do about 50% water change to replace the hot water. Check the temperature if it is in the previous level before putting your shrimps.

You can also run very cold water into your tank. But the problem is that the hydras may also go dormant instead of dying.

a shrimp tank setup with live plants
Owner: Ricky Sales

7. Using Light Trap

You may have noticed hydras on the front glass of your shrimp tank. That is because hydra is responsive to the light. This can be a great weapon in this fight.

  • Turn off the light of your tank.
  • Put a piece of glass behind your front glass.
  • Use a flashlight or any bright light that will pass through both the glass layers to attract the hydras.
  • After a few hours, you will notice the hydras have moved to the light and sat on the second piece of glass.
  • Remove that second glass from your tank with the hydra on it.
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Though you cannot attract all the hydras and take in that glass, it will reduce the population noticeably.

8. Using Sea Salt

Another safe way according to the shrimp keepers to kill the hydra. Hydras are sensitive to sea salt, iodine-free table salt.

Use 2gm table salt per 1 liter of your tank water. API Aquarium Salt can be a good product to go with this mission.

9. Siphoning Them While Changing Water

Since hydra can grow to half an inch, you can also siphon them out while doing a water change. Make sure you do not siphon out your shrimps.

10. Using chemical

a. H2O2

H2O2 will effectively kill the hydra colony without causing any damage to your shrimp tank.

Turning off your filter evenly spread 14.3 ml H2O2/L across your tank surface for safely killing the hydras. An overdose of H2O2 can even kill your shrimp so measure your tank water before applying it.

After an hour turn on your filters. Do a water change within that week and then you can add a bacterial supplement.

It is safe for your tank cycle and can only damage some biofilm.

 b. Fenbendazole

Safe-guard canine dewormerPanacur ® C are some other effective fenbendazole products to remove hydra from your shrimp tank. Use in the same way as it is instructed to use against parasites.

c. Potassium Permanganate, Copper Sulfate

Potassium Permanganate, Copper Sulfate also destroys hydra effectively but do not use them until you have tried the other options.

  • Make sure that you follow the dosing and all the instructions on the product exactly.
crystal red shrimp in planted tank
Owner: Ricky Sales

How To Prevent Hydra From Entering Into Your Shrimp Tank?

Pre-treat your plants well

Try to buy your plants from a good store. Thoroughly clean your plants before introducing them to the tank.

For more protection dissolve a tablespoon alum in a quart of water and bathe the new plants for 5-10 minutes and after that rinse well with plain water. You can also treat the new rocks like this.

Buy shrimps from a reliable source

Also, hydra can be transferred to your tank when you are buying shrimps from the large pet store chains. So, collect your shrimps from a reliable store.

Clean your tank

Good maintenance can be an effective way to prevent hydra from your tank.  Clean your tank regularly to minimize the risk of the hydra.

When you overfeed your shrimps, they do not eat all food which later on makes your tank dirty. Hydras like such dirty tanks and can eat those decaying foods. So, remove any leftover of your shrimp food. While it is a little hassle on your part, it is better to put feeding dishes in your tank.

According to shrimp expert Abhisek Mallick, effective shrimp care is more about prevention than cure.

Maintaining a clean and well-balanced shrimp tank is crucial, as Mallick emphasizes, ‘It’s better to be proactive than reactive.’ Regular cleaning and controlled feeding can prevent the conditions in which Hydra thrives.

Mallick also warns against the use of insecticides near the tank and advises caution with tank additives, noting that substances like active soil, Indian almond leaves, and alder cones should be used judiciously to avoid drastically lowering pH levels, which can be detrimental to shrimps.

Frequently Asked Questions

Can Hydra move from one place to another?

Generally, Hydra are sessile so stay in one spot but they are capable of changing their place.

Although they cannot swim like your shrimps, sometimes you will notice them hover around your tank. That is when they want to take a position at a better location.

With Hydra’s tentacles and suction-pad like base, they can detach and somersault across a surface in your tank. In this way, they can move up to 10 inches in a day.

To move to a longer distance, hydras use their suction grip on the surface and take the help of the current.

How Do Hydra Prey?

As Hydra do not move significantly, they will not conduct a “hunt” on your shrimps. Rather they will wait for their prey to come enough close to them so that they can catch them with their tentacles.

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Hydra releases and fires neurotoxins from their nematocysts (very small stinging organelles) and paralyzes their prey. When the prey comes in contact with them, they get stimulated by chemical signals and targets the neurotoxins to their prey.

As the prey is paralyzed, they bring it to their mouth and later into the body with the tentacles. It takes very little time to sting and immobilize the prey.

How does hydra enter your tank?

So, you are not getting how these little Hydras come into your shrimp tank. Well, you also have done some favor to get them into your shrimp tank. Here are some of the ways they can enter a shrimp tank:

With a fish bag:
Hydra can creep into your tank with the water from your fish bag while putting a new shrimp. Since they can withdraw their tentacles and close up, they look like floating debris and can easily avoid your sight.

With your plants
Hydras are great stowaways and enter with the new plants, wood, or rocks to your tank. Even after being careful, you may experience hydras in your tank.

How will you recognize Hydra?

In the beginning, hydras are even smaller which will look like little white spots in your tank water. As they mature, they will start becoming a little white stringy creature that will also be successful to deceive your eyes.

Once Hydra will appear to the glass or any black surface, you will be able to see their unusual appearance.

But the problem is they cling to any surface in your aquarium – plants, wood, rock, sponge filter making it hard to trace them. You may be unaware of their first entry in your tank, but do not worry, you will notice them soon because they will multiply unbelievably!

So, if you notice one or two of them, be sure that the rest of the colony has already set up on your tank.

How fast can Hydra reproduce?

If Hydras get favorable surroundings, one hydra can produce up to 15 baby hydras a month. These new hydras are also able to produce more hydras just like their parent hydra.

Hydras reproduce by budding. The bud at the base of their body gets mature enough and break off and turn into another hydra while the newbie will have another bud and thus give birth to another hydra.

So, close your eyes and just calculate how fast they can spread in your whole tank. A single hydra will lead to hundreds within a very short time.

Thus, from one hydra, 4,000 new hydras will be introduced in your shrimp tank in just 3 months!

Are chemical options better for destroying the Hydra colonies completely?

Chemical or medicinal bath treatments can remove Hydra completely, but they can cause potential harm to your shrimps, live plants, snails, beneficial bacteria of the biofilter.

So, opt for these treatments only when you cannot cope with the hydra colonies or siphon them out manually.

Does No Planaria kill Hydra?

No Planaria is a shrimp-friendly product for removing the hydra colony from your tank. The name suggests that it is for Planaria but it also kills hydra effectively within a few days.

How do you get rid of hydras naturally from shrimp tank?

Hydras in shrimp tanks can be eliminated naturally by introducing natural predators such as snails or fish to the tank, cutting out their food supply, and maintaining proper tank conditions and avoiding overfeeding.

Will Hydra go away on its own?

Hydras do not go away on their own and can actually multiply rapidly and take over an entire tank.

What temperature kills hydra?

To kill hydra in an aquarium, the water temperature should be increased to at least 104 degrees Fahrenheit (40 degrees Celsius) for about two hours.

Afterward, the heat should be turned back down, and a large water change of approximately 50 percent should be performed to remove the hot water and any dead hydra.

What snails eat Hydra?

Ramshorn snails, Pond snails, Spixi snails, Mystery snails, Apple snails, and Nerite snails are known for eating Hydra.

What fish eat Hydra?

Guppies, Gouramis, and Siamese fighting fish (Betta) eat Hydra.

However, introducing fish to a tank solely for the purpose of controlling hydra may not be a good idea, as some fish may not be compatible with other tank inhabitants or may require specific water conditions. 


While hydra is practically impossible to prevent from entering your shrimp tank, they are easy to get rid of if you try these methods. So, if you have noticed their entrance in your tank, do not be anxious because they will not put an end to your shrimp colony within a night.

Rather, deal with hydra trying the most suitable method for your tank at the earliest to avoid any possible loss to your shrimps. 

Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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