Majano Anemones; A Beautiful Pest

We received a shipment from Vietnam that was to have included a few assorted Rock Flower Anemones, an often strikingly beautiful species that adds colour and texture to the reefscape.  What we received however were small palm sized pieces of live-rock each of which had approximately 10 to 15 small, knobbly, variably coloured and seemingly attractive anemones. They were definitely not Rock Flower Anemones.

To the uninitiated these would appear at first glance to be quite desirable. They might even be confused with small Bubble-Tip Anemones.  They were however Majano Anemones (Anemonia manjano), less well known but as problematic as Aiptasia. These anemones will proliferate in an aquarium and sting any other corals that they come into contact with.  And, they are incredibly difficult to eradicate once established. To illustrate the point, each of the pieces of live-rock that they arrived on had no other signs of life, it was as though they had completely taken over.

If you do get these anemones in your reef tank, you can try to tackle the problem in the same way as you might Aiptasia; natural predators such as Copper Band Butterflyfish, Matted Filefish and Peppermint Shrimp maybe introduced to the aquarium.  Alternatively, if you can access the anemone, the direct application of remedies such as lemon juice, scalding hot RO water, calcium hydroxide (Kalkwasser) or Red Sea’s Aipasia X through a syringe should kill it.

The safest and simplest way of course is to familiarise yourself with the Majano and avoid introducing it in the first place. Majano Anemones grow to about 3cm across and resemble small bubble tip anemones (BTA). They have a brown/green pedal column with a foot that attaches to the live-rock and allows them to move around. The oral disk has a mouth in the centre and is covered in tentacles of varying colour, mostly brown/purple and fluorescent green. The tentacles are swollen towards the tips giving the appearance of a small BTA. They reproduce prolifically given the right conditions.