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Living Organism Care Hydra
Living Care Information
Hydra littoralis or viridissima
commonly known as Hydra
Quick Start Information
Upon arrival, immediately remove the lid and gently aerate the culture using the provided pipette.
Keep the culture in dim light, at a temperature of about 21º C (70º F). Hydra can live for about 3-5 days in the water in the culture jar. Green Hydra cultures require supplemental lighting.
Hydra cultures can be refrigerated for 1-2 weeks without feeding, however, this will reduce their size.
About the Organism
- Biologists are very interested in hydra because of their regenerative abilities. They also do not die of old age or show any age related declines.
- Hydra do not have a recognizable brain or true muscles.
- When hydra are alarmed, their tentacles can retreat into small buds. They can also condense their body down to a small gelatinous mound to avoid injury.
- Hydra are generally sessile, but do move in short bursts especially while hunting
- Our Green Hydra form a symbiotic relationship with Chlorella.
- Domain: Eukarya
- Kingdom: Animalia
- Phylum: Cnidaria
- Class: Hydrozoa
- Order: Hydrioda
- Family: Hydridae
- Genus: Hydra
- Species: littoralis or viridissima
Preparation
Hydra are available year round as we offer both lab cultured and collected specimens. Our Hydra cultures are shipped in plastic jars containing water from our culture. We do include extra specimens as some die off may occur as a result of the shipping process. For best results, we recommend cultures of Hydra should be used the same week they are received. After a couple of days without a feeding, Hydra will begin to shrink in size. If you plan to keep your Hydra for longer than 3 days after receipt, we recommend that you implement a feeding and water change regime. See below for information on procedures.
Housing
If you plan to keep the Hydra longer than 3 days after receipt, they can be housed in an aerated aquarium, tub, or small glass container such as a culture dish. If using a smaller container with a small volume such as a culture dish, 1/3 of the water should be siphoned off daily and replaced. Natural Spring water is required for keeping Hydra.
Water temperature should be kept between 18°C–21°C (65–70°F), and the pH should be at 7.5–8
Feeding
Since Hydra are predators, they need live food. We recommend Daphnia pulex or newly hatched brine shrimp. For instructions on hatching brine shrimp, see our brine shrimp living care guide under Preparation.
Hydra should be fed daily. The food can be added directly to the water. Start the feeding at one pipet of food, then adjust the feeding according to how quickly the food is eaten or how much food is left in the bottom of the container. Green Hydra can survive for several weeks without food as long as they have adequate light. It is still necessary for green Hydra to be fed brine shrimp larvae or daphnia for long-term health.
Maintaining and culturing
If housing the Hydra in larger containers, such as an aquarium or tub, Water changes should be performed weekly to remove uneaten food and accumulated bacteria. We recommend that you siphon any uneaten food from the bottom of the container to remove it as well as any bacteria that has accumulated. Water that is cloudy or foul should be removed and replaced with natural spring or bottled water only.
These requirements make maintaining Hydra in culture very demanding.
Disposal
Hydra can be euthanized by pouring a capful of household bleach into their container and washing the contents down the sink with plenty of tap water.
Biosafety
Be sure to wash your hand with soap and warm water after handling any living specimen, cleaning tank water or handling tank components.
Video
FAQs
Which Hydra should I use to demonstrate feeding?
A good choice is item #132800 Hydra littoralis (brown Hydra) with Daphnia pulex for the food source. Green Hydra are usually too small to engulf D. pulex, and D. magna is too large for even brown Hydra to engulf.
Our Hydra appear sick. What’s wrong with them?
During the sexual phase of their life cycle, Hydra put most of their energies into producing sperm and eggs. They contract and appear ill. This happens more frequently during the spring.
Our Hydra were doing well, then they all disappeared. What happened?
It is difficult to maintain a small culture of Hydra for more than a few days. Also, Hydra are delicate animals, easily damaged when moved onto a slide for observation. Plan on using the Hydra as quickly as possible after receipt.
Why are our Hydra getting smaller?
Hydra slowly shrink if they are not fed. This is another reason to use them as soon as possible.
Some of our Hydra have growths on their sides. Is something wrong with them?
Hydra reproduce asexually by buds that grow from their sides, which develop into a new Hydra. Hydra also reproduce sexually. During this stage of the life cycle, they develop lumps on their sides. These lumps are the ovaries and testes.
Need help?
We want you to have a good experience. Orders and replacements: 800.334.5551, then select Customer Service. Technical support and questions: caresheets@carolina.com
