Sea Anemones, Actiniaria

---

Description:
   Anemones are invertebrates, as are 95% of the earth's creatures. Most invertebrates are insects. The name Cnidaria (with a silent "c") refers to the cnidae, or nematocysts, which all Cnidarians have. The phylum Cnidaria includes anemones, corals, jellyfish, and hydras. The 'cnidae' are the stinging cells which provide the animals a means of capturing prey and/or defending themselves with a painful sting. Another name for Cnidarians is Coelenterata (pronounced "se-len-ter-a'-ta') which refers to the single body cavity that serves as stomach, lung, intestine, and everything else! There is only one opening into this cavity, the mouth, through which everything passes in and out. The mouth is surrounded by several or many tentacles which contain the nematocysts (cnidae) at their tips. Sea anemones, being members of the Class Anthozoa, along with hard and soft corals, are benthic, which means they are attached to rocks or the sea floor. Anemones in the aquarium though, will often move around until they find a place that they like and then stay put!

   Most anemones survive in a symbiotic relation with with a marine algae called zooxanthellae. The zooxanthellae are photosynthetic organisms whose waste products are used by the anemone for food. Since the zooxanthellae require light to carry on photosynthesis, anemones in turn require bright light to thrive in the aquarium. The zooxanthellae are generally a light brown color, the same color as the light brown leather corals that also harbor zooxanthellae. The loss of zooxanthellae, apparent by a whitening of the anemone, usually means the anemone will slowly grow smaller and smaller until it dies.

Care and Feeding:
   We have found that anemones are often challenging. One of the best books we have found, and the main reference for information presented here, is the book "Field Guide to Anemonefishes and their Host Sea Anemones" by Daphne G. Fautin & Gerald R. Allen. Both of these authors believe that carpet anemones should not be removed from the oceans for the aquarium trade. We have purchased almost every anemone available and have read surveys taken in an attempt to determine the survival rate of anemones once they enter into the aquarium industry. In both cases the survival rate is very low, particularly among the larger carpet anemones which are the natural hosts to anemone fish. This doesn't mean that clownfish won't take other kinds of anemones as hosts. The best anemone survival rates that we have found are among the smaller anemones and one carpet anemone, the saddle anemone. Another that is very common is Entacmaea quadricolor, the purple base or pink tip anemone. This is fortunate since many different kinds of clownfish will accept the purple base anemone as a host.

   Many anemones need lots of light (2 to 5 watts per gallon) preferably with some blue spectrum provided by actinic light bulbs or higher temperature metal halide lighting. The scale of light intensity is:
     Low level - 1 to 2 watts per gallon, about a normal marine setup with regular fluorescent bulbs (10 watts per foot bulbs).
     Medium level - 2 to 4 watts per gallon, maximum regular fluorescent to minimum VHO or metal Halide.
     High level - 5 or more watts per gallon, maximum VHO and/or metal halide.
See Mini-reef: Lighting for a description of VHO and metal halide.

---

The Best Book on Anemones and Clownfish

Anemone Fishes and Their Host Sea Anemones

---

Genus: Aiptasia

   This anemone is so hardy it is considered a pest in mini-reef aquariums. Many articles have been written on how to get rid of them, from injecting them with kalkwasser, to using aquastick (an underwater epoxy) to seal them into a hole in the rock! Apparently if they are smashed or removed by hand, small pieces of the anemone will re-grow to adult Aiptasia. Aiptasia are not used by clownfish probably because they are too small.

---

Curlicue Anemone

   We are not sure what the scientific name of this anemone is. It has beautiful, delicate tentacles. It prefers medium to high light conditions but will survive in low light as well. This is not a clownfish host.

---

Bubble Anemone- with two Sebae Clowns
Heteractis dorensis

   This is a hardy anemone that likes medium to strong light and does well in aquariums. Many different kinds of clownfish will accept it as a host. We had a pair of Cinnamon clowns breed in a bubble anemone repeatedly for over a year. Pictured with the anemone above are Sebae clowns.

---

Tube Anemone
Pachycerianthus mana

   Tube anemones are one of the few that do well in low light levels. They are nocturnal and should be fed chopped fish and shrimp every other day or so. They build a tube out of mucus and detritus found on the substrates they inhabit. Tube anemones are found in all the warm water oceans of the world. Their long tentacles have a powerful sting and therefore should be kept away from other anemones and corals. They are not used as hosts by clownfish.

---

Color Variations

Caribbean Anemone Condylactus gigantea

   These are an inexpensive anemone which come from the Caribbean. They are usually very hardy and come in several colors. The most attractive have purple tipped tentacles. Condylactus like high light levels but will do okay in low to medium light. These anemones are the most inexpensive and are very hardy. They can do well in any marine aquarium, not just reefs!

---

Long Tenacled Anemone
Macrodactyla doreensis

   This anemone will get fairly large (we have one that is the size of a dinner plate) and is accepted by many different kinds of clownfish. We have personally seen Tomato, Sebae, Percula, Skunk, and Maroon clowns accept it as a host. They are usually hardy and easy to keep as long as you have medium to strong light.

---

   This looks like a variety of tube anemone but we're not sure.

---

Saddle Anemone
Stichodactyla haddonni

Photos © Animal-World

   The Saddle anemone, pictured above, has a lot of very short tentacles. They are very adhesive to human skin. If you touch one it will stick fast, sometimes to the point of pulling the tentacles out of the anemone when you detach it. There is a rarer form of the Saddle anemone which has lighter stripes running from the mouth (center) to the outside edge. The Saddle anemone is by far the hardiest of the carpet anemones. It likes strong light levels.

---

Back to Coral Reef

---