Sea anemones are predatory marine animals, relatives of corals and jellyfish, with distinct nutritional requirements for their well-being in a home aquarium. These invertebrates depend on proper care and feeding to flourish, making an understanding of their nutrient acquisition a primary step for any hobbyist.
Natural Diet and Photosynthesis
In their natural ocean habitat, anemones use a two-part strategy to meet their energy needs. The most visible method is active predation. Using tentacles armed with stinging cells called nematocysts, they capture prey that drifts within reach, such as small fish, plankton, and shrimp. The tentacles immobilize the food and draw it into the central oral disc, which functions as the anemone’s mouth.
A less obvious but equally important nutritional source is a symbiotic relationship with algae. Many anemone species host microscopic algae called zooxanthellae within their tissues. These algae perform photosynthesis, and a significant portion of this energy is transferred to the anemone, serving as a substantial food source. For this reason, providing high-output lighting is a form of feeding for these anemones.
Appropriate Foods for a Home Aquarium
To supplement the energy provided by lighting, captive anemones benefit from direct feeding with appropriate foods. The best choices are raw, marine-based meaty foods that mimic their natural diet. Excellent options include:
- Mysis shrimp
- Krill
- Silversides
- Clams
- Scallops
These can be purchased frozen from aquarium suppliers or fresh from a grocery store, provided they are unseasoned. Commercially prepared foods formulated for corals and anemones are also available.
The size of the food offered is a significant factor. Food pieces should be cut small enough to be easily managed by the anemone, relative to the size of its oral disc. For smaller anemones, a quarter-inch piece is often sufficient. Offering food that is too large can lead to regurgitation, which can negatively impact water quality if left to decompose. Avoid feeding terrestrial meats, as these are not part of their natural diet and are difficult to digest.
Feeding Technique and Schedule
The frequency of supplemental feeding depends on the anemone’s species, size, and the intensity of aquarium lighting. Anemones under powerful lighting systems derive more energy from their symbiotic algae and require less frequent direct feeding. A general guideline for most anemones is to offer food once or twice per week. If an animal consistently rejects food, it may not be hungry.
The most effective feeding method is target feeding. This involves using tools like long tongs, tweezers, or a turkey baster to gently place food directly onto the anemone’s tentacles. This precision ensures the anemone receives the food before it is stolen by fish or shrimp. To prevent the food from being blown away, turn off aquarium pumps and powerheads during feeding, allowing the anemone time to grasp the food.
Signs of overfeeding include the anemone spitting out food hours after it was consumed. If this occurs, it is a clear indication to reduce the size or frequency of feedings. If clownfish are hosted by the anemone, they may also bring food to it, reducing the need for manual feeding.