Are Hydra Harmful?

By Ryan Wood

Besides fish there can be other aquatic inhabitants that can cause harm or kill shrimp. One creature believed to cause harm or kill shrimp is the Hydra. Hydra are from the Coelenterata family of aquatic invertebrates. Other members of this family include corals, jellyfish, and anemones which are primarily saltwater. One thing to notice is that all of the previously mentioned relatives of the Hydra can also cause harm to other aquatic creatures by methods of stinging, poisoning, etc.

Like its saltwater relatives the Hydra uses its tentacles to capture prey. It stings its prey before feeding. It uses its tentacles as pseudo fish lines with barbs to capture small prey, including crustaceans, and feed by bringing the dead prey to its mouth located in in the round portion of the creature. The Hydra is known to feed on small fish fry and some have reported it feeding on small to large shrimp.

Due to the potential for this creature to cause harm on your shrimpit is recommended that you attempt to irradicate it. The Hydra however is not easy to completely remove. Chemicals that would otherwise work to kill Hydra will also harm your shrimp at the same time. Hydra are invertebrates just like shrimp so anything that can harm a Hydra can harm a shrimp. There are however a few keys to keeping Hydra out of your aquarium:

Prevention: Another thing to remember is that Hydra tend to enter an aquarium attached to plants recently purchased. Just like snails, Hydra can hitchhike along with the plants ending up in your aquarium. Make sure that you purchase your plants from a reputable source. Some of the best places to purchase plants online are from other hobbyists through forums. If you purchase plants from a local pet store, or a large chain, you have a very high risk of introducing potential problem creatures. Rinse your plants before you introduce them into your aquarium regardless of where you got them from.

Maintenance: Keeping a clean aquarium is one of the keys to controlling and/or removing Hydra from an aquarium. Just like Planaria, Hydra thrive in dirty tanks. Overfeeding can result in a dirty tank. Only feed your aquarium inhabitants what they will eat in 2 hours. Any leftover food must be removed. If you overfeed you greatly decrease your chances on keeping Hydra out of your tank.

Removal: If you see Hydra in your aquarium there are a few methods to removing them. Netting them is the obvious one since the Hydra can reach up to half an inch in size. Using a brine shrimp net you may have luck netting them. Another method is sucking them through a tube during water changes. Be very careful that you do not suck up shrimp while trying to remove the Hydra.

Don't panic if you see Hydra in your aquarium. Follow a few easy steps to prevent, maintain, and remove them. Do not use chemicals.