Beadlet Anemone (Actinia equina)

…a species of sea anemone that can be found on the rocky coasts of the United Kingdom, Western Europe and the Mediterranean. This anemone is highly adapted to its environment and can thrive in high temperatures and dryness, some have even been found in areas with low salt. They also possess a ring of blue tentacles called acrorhagi which are used to fight off other anemones that attempt to invade their space.



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Beadlet anemone  (Tomate de mar)

Actinia equina (Actiniaria - Actiniidae), the Beadlet anemone, is a considerably versatile intertidal sea anemone, with a wide array of color variation, from green to red. The most common hue is rust-red.

In the beadlet anemone, the tentacles (up to 192) are arranged radially in six circles around the mouth (the opening to the gastrovascular cavity). Bright blue spots (shown in the photo), called acrorhagi, are below the tentacles on the outer margin of the column and look like warts.

This sea anemone is found primarily in the North Atlantic Ocean and the Mediterannean Sea, but populations also exist stretching down along Africa’s Atlantic coast.

Reference: [1]

Photo credit: ©Jeroen Zetz

Locality: Scherpenisse, Zeeland, Netherlands


Beadlet anemone (Actinia equina)

Taxonomy: Animalia, Cnidaria, Anthozoa, Hexacorallia (subclass), Actiniaria, Actiniidae, Actinia, A. equina

Description: Single polyps reach 5cm in width, with up to 192 tentacles in 6 rows. The column is smooth, and coloration ranges from red to green. At the base of the tentacles is a ring of acrorhagi, which are often described as looking like small beads. Outside of water, A. equina appears to be a jelly-like blob.

Lifestyle: A. equina can be found on rocky shores throughout Great Britain and Northern Ireland, and in water up to depths of 20m. As with many intertidal organisms, A. equina can tolerate a variety of temperatures and salinity levels. They are carnivorous, and capture prey with their tentacles- this prey ranges from crustaceans to small fish.

Images from ARKive.

Beadlets are pretty cool anemones, especially in terms of their territorial behaviour. If they feel that another beadlet is too close to them, they inflate their acrorhagi and hit the opposing anemone with them- the nodes contain nematocysts- stinging cells- and are only used for fighting other anemones of the same species. The nematocysts leave visible markings on the anemones they hit (an example of which can be seen here).

Beadlets are also interesting in that they are viviparous- they give birth to live young. Embryos develop inside the body before being released as juveniles.

Beadlet anemone / ウメボシイソギンチャク

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Actinia equina

The colony of Beadlet anemones. ウメボシイソギンチャクの群れ。

Animalia Cnidaria Anthozoa Actiniaria Actiniidae
動物界 刺胞動物門 花虫綱 イソギンチャク目 ウメボシイソギンチャク科

Photo taken at Tokyo Sea Life Park, Japan

Beadlet Anemone
Genus: Actina
Species: A. equina
Maximum Size: 2" across
Aggression: Non-aggressive
Temperature: 64-68 F
pH: 8-8.5
Hardness: 15-25 dH
Brackish Tolerance: 1.015-1.025
Minimum Tank Size: 5 gallons
Feeding: Mysis Shrimp, brine shrimp, krill, chopped shellfish
Notes: Unlike the majority of Anemones and Cnidarians available in the marine trade, the Beadlet Anemone is very tolerant of salinities outside of full strength seawater (1.023-1.025) and is often found in estuaries. Also unlike most other Anemones, the Beadlet Anemone is not photosynthetic and derives all nutrition from purposeful feeding, which should be done weekly. They are also tolerant of subtropical conditions, but do not grow to their full size in these conditions. The Beadlet Anemone is the only Anemone species to perform viviparious reproduction, and purchasing a few specimens will allow for them to breed in the home aquarium.

Although not aggressive, they do sting and thus should not be kept with fish that are unable to avoid swimming into them. Few brackish, coldwater fish exist that fit this profile and are available in the trade. One is the Peacock Blenny (Salaria pavo) that is occasionally sold. All things considered, the Beadlet Anemone probably should not be kept with fish in brackish systems.


FAQs on Cool to Cold Water Anemones, Wetwebmedia

Actinia equina, Animal Diversity Web

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