Sea anemones

Stinging invertebrates that host clownfish in symbiosis. Beautiful but demanding: they require intense light, perfect water and a mature aquarium.

Detailed explanation

Sea anemones are cnidarians closely related to corals. In the aquarium the most common species are Entacmaea quadricolor (bubble tip anemone, the most adaptable), Heteractis magnifica, Heteractis crispa and Stichodactyla.

Entacmaea quadricolor is the best choice for reef beginners. It adapts to different light conditions, easily accepts clownfish and reproduces by splitting in the aquarium (splits in two). The coloured shapes (rose, rainbow, sunburst) are highly sought after.

Anemones need a mature aquarium, at least 6-12 months functioning. The parameters must be stable: KH, calcium, magnesium in the optimal ranges. The lighting must be intense (200-400 PAR depending on the species).

The main problem with anemones is that they move. They don't stay where you put them. They walk with their foot looking for the spot with ideal light and flow. During their movements they can end up in the circulation pump or burn the corals they touch with their tentacles.

Covering grids or sponges are used to protect the pumps. It's not an option: it's mandatory. An anemone sucked into a pump dies and pollutes the entire aquarium.

Direct feeding (a small piece of shrimp or mysis placed on the tentacles once a week) accelerates growth and improves colours. Zooxanthellae provide most of the energy but supplemental food makes a difference.

When an anemone is not well it shrinks, loses colour, releases mucus and can detach itself from the rock and float in the aquarium. If it dies in the aquarium it must be removed immediately because decomposition releases toxins that are lethal for the other inhabitants.

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