Anemones are basically simple, primitive animals. They range in size from one-half inch to over four feet in diameter. Their tube shaped body is usually topped with a ring of tentacles, which selectively feed on planktonic organisms or small fishes. A ring of tentacles surround an area known as the oral disc, which contains an opening in the center commonly called the mouth. Food is taken into this opening and waste matter or undigested food is expelled through the same opening. The body column sometimes referred to as a pedal column, serves as a means for locomotion or as a holdfast.
Should environmental conditions not be suitable, anemones can easily move to where light, water movement and feeding conditions are more favorable. A moving anemone is a sign it's unhappy with its environment! Anemones may reproduce sexually or asexually by splitting and fragmentation. With some anemones, asexual reproduction results in the production of clones. Clones of the same specimen can intermingle without any harm to each other. Yet clones of a different individual, even though the same species will do battle with each other. They have been known to live in captivity for almost eighty years.
All anemones are considered carnivorous even though some utilize intense light to trigger symbiotic algae living in their flesh, which in turn produce a portion of their nutritional requirements. Using small nematocysts or stinging cells, which cover the tentacles and which are capable of firing a tiny dart connected with a thin filament into its prey, the anemone is very capable of capturing planktonic organisms and small fish. Anemones have few enemies, with other anemones, nudibranchs, sea stars and some fishes considered their main predators.
Anemones have specialized defensive mechanisms that can deter potential predators, e.g., specialized nematocyst at the base of the tentacle; inflating defense tentacles called 'acrorhagi' located just below the oral disc; reducing body size; and, exuding quantities of nematocyst-laden mucous called 'acontia.'
Even though most anemones are considered carnivorous, some that interest aquarists require bright light to trigger their symbiotic algae. If conditions are not suitable, they will move to where conditions will suit them. Therefore, in a mixed anemone and coral environment it's recommended the anemone be placed in the aquarium prior to adding corals so as to allow it to find its own favorite spot. That way, the anemone passing near or over it will not damage stationary corals.
Clownfish domination of host anemones is simply nature's way for the fishes' survival. In the wild, very large anemones can be found with hundreds of different types of clownfish living in a symbiotic relationship with "their" anemone. With lots of anemones to go around in the wild, the living conditions are quite different than in the aquarium. With only one anemone in the aquarium, the strongest clownfish will dominate and weaker ones will be driven out. If all the clownfish are added at the same time there is a better chance they will all settle down and live together in the same anemone. I find long tentacle Pacific anemones are by far the best choice for keeping clownfish happy and healthy. However, keep in mind the anemone must be of sufficient size, i.e., at least five inches across, or the clownfish may cause such disturbance that the anemone is unable to feed itself.
Two of the best publications to view most of the anemones of interest are: "Field Guide to Anemonefishes and their Host Sea Anemones" by Daphne Fautin and Gerald Allen, and "Sea Anemones...as a hobby" by U. Erich Friese.
When it comes to selecting anemones, always make sure their coloration is very good, their central orifice is not misshaped, the foot area and tentacles are sticky, and that the shop clerk does not damage the foot area when removing it from the store tank. Many of the more popular anemones need good lighting intensity to survive, i.e., 4 - 6 watts per gallon. As for water temperature, that's generally in the 75 - 82°F (24 - 27°C) range unless noted differently below, with salinity between 1.024 - 1.027. Also, good water movement is usually a key component for long-term success.
As for feeding, small pieces of silversides, shrimp, krill, fresh fish flesh, and/or whole fishes fed once to three times a week mostly suffice. Place the food morsel on the tentacles or near the central orifice. Only one anemone per tank is recommended unless the aquarium is over 100 gallons in size. And, keep in mind aggressive stony corals such as Euphyllia and Galaxea with long sweeper tentacles and large soft coals such as leather corals that compete for space with chemicals are not good tankmates.
Host anemones of great interest are the bubbletip Entacmaea quadricolor, or the more erect column anemone H. magnifica, as are the long tentacle anemones, Macrodactyla doreensis, and what are called carpet anemones with even longer tentacles, e.g., Stichodactyla mertensii, S. haddoni, S. gigantea. There are also some other anemones of interest, and those are included below.
Condylactis anemones are not generally accepted by clownfish. They should not be kept in an aquarium with corals or Pacific anemones as they are quite aggressive and may damage these organisms. They prefer sandy bottoms and are very sensitive to mishandling. It is a low priced anemone and not truly suited for use in the multi-organism environment associated with reef aquariums.
This very popular anemone hosts 13 clownfish species depending upon its geographic location. In the Red Sea, the anemone is host to Amphiprion bicinctus, in the Indian Ocean it serves as host to A. allardi and A. clarkii, in the Indo-Pacific it forms symbiotic relationships with A. ephippium, A. frenatus, A. melanopus, A. chrysopterus and Premnas biaculeatus, and off the coasts of Australia, A. akindynos, A. mccullochi and A. rubrocinctus (Schiemer/99).
The cause of its bulbous tips is still not resolved, but Delbeek and Sprung (1997) believe light intensity is the main factor for their shape. Reproduces asexually via longitudinal fission (cloning) and attains a diameter of about 16 inches.
One of the more common aquarium anemones in the trade because it's easy to collect as it occurs on sandy and muddy bottoms. Yet, only a fairly good clownfish host anemone.
All are good clownfish hosts, however they require adherence to their preferred logistics and most are feeders of prey that are normally found on the bottom and/or small fishes (feed the whole fish/shrimp).
Contains only one species of interest and generally houses the shrimps Thor and Periclimenes. Very sticky and may sting unprotected hands. Hosts very few anemonefishes.
These small brown rock/glass anemones are considered here only because they usually become pest-like in aquaria. Their sting can cause most corals to close-up and remain closed, and unfortunately they multiply quickly.
There are a few species of interest, e.g., A. pallida, A. pulchella, and A. diaphana, however, they all look alike to the layperson. They come from a wide range of localities and withstand a wide range of temperatures. Bottom line, it's the 'how to rid the aquarium of them' that is more important than 'how to maintain them!'
There are various ways to reduce and keep the population to a minimum, but there is no sure fire cure to rid the entire aquarium of this pest once it has gotten a foothold. If the hobbyist has a fish-only aquarium, they could introduce a Raccoon Butterflyfish (Chaetodon lunula), Klein's (C. kleinii), the Saddleback (C. ephippium), Tinker's (C. tinkeri), the Threadfin (C. auriga), or the Copperband (C. striatus ) which will eat these pests. Yet, should there be corals, feather dusters, star polyps or zoanthids in the aquarium, these fish will probably feast on them also.
Injecting it with boiling water or very hot Limewater causes it to turn a grayish color, effectively killing the entire specimen. Yet, sticking a needle into the anemone before it can withdraw is almost impossible. Locating a hypodermic syringe filled with hot Limewater about a quarter inch away from the anemone and shooting a stream of hot Limewater upon the anemone stuns the anemone and seems to prevent it from withdrawing/shrinking in size. It is then fairly easy to get the point of the needle into the still erect body and injecting it, effectively killing the specimen.
Another idea is using the sting from an Elegance coral (Catalaphyllia jardinei) to kill the anemone. This does work, as I have tried it!
Another way to destroy these pest anemones was brought to my attention by a fellow hobbyist in New York. He notes that a slush mixture of sea salt deposited directly on the anemone will cause it to immediately die. Simply take some aquarium sea salt and make a slush-like mixture and flow it directly on the anemone. A syringe is a good way of applying this mixture. It can also be flowed into cracks getting it down to where these pests may have a foothold.
The Nudibranch Berghia verrucicornis, native to the Caribbean and western Atlantic, only feeds on Aiptasia anemones. Juveniles measure about 1 cm, with adults reaching 3 cm within a couple of weeks. They are nocturnal. Unfortunately, once these pest anemones are eliminated, the Nudibranch will die because of a lack of food supply. Of course, you could pass it along to a fellow hobbyist who has some of these pest anemones. This way, the Nudibranch may still be available should they return to your aquarium in the future. Also, other Nudibranchs that may be effective are Spurilla neopolitana and Baeolidia nodosa, however, their availability is questionable.
A recent biological control is thought to be the Red-legged hermit crab, Dardanus megistos. This small hermit appears to be safe in reef aquarium and is thought to dine on this pest anemone. Yet more than an occasional positive feedback is still needed to confirm its usefulness.
Another biological control is through the use of Lysmata wurdemanni, usually called the Peppermint Shrimp. This 2.5 inch (6 cm) shrimp has lengthwise lines of red covering a somewhat transparent body. It does not have claws like the Banded Coral Shrimp, however is an effective killer of Aiptasia anemones. However, they appear to also consume Yellow polyp anemones.
Scats (Scatophagidae), which are a brackish and/or freshwater fish, are also a very good consumer of Aiptasia anemones. They not only take a wide variety of foodstuffs, including copious amounts of vegetable matter, they also like these rock anemones.
Another possible solution is the use of a little known Filefish, Acreichthys tomentosus. It is said to reef safe, yet most filefishes are far from reef safe. Caution is advised.
Novel approaches such as the use of peppery hot sauce is not recommended, nor are chemicals such as hydrogen peroxide, hydrochloride acid or copper compounds. However, there has recently (late 2003) been another entry into controlling these pests with a foodstuff that is sprinkled over the anemone and after consuming this material, the anemone melts away. Said to be harmless to other invertebrate and works quite well in reef aquariums. Contact "www.joesjuice.com for more information.
I don't have much information on this species, however, it is in the same 'pest' class as Aiptasia anemones. It's a small somewhat green anemone (w/green/yellow stalk) that looks similar to a miniature bubble anemone. They reproduce quickly, and like Aiptasia anemones, sting anything they touch. Natural predators include Centropyge, Apolemichthys, and Pomacanthus Angelfishes. Also, the Peppermint Shrimp. Delbeek and Sprung report it comes in as a hitchhiker on rock from Fiji or Indonesia.
A common anemone in the Caribbean, often with as many as 200 transparent tentacles. A very good fish eater and will severely sting corals. Not something for the fish-only or reef tank!
Tube anemones are bottom burrowing animals and are better maintained under low light with little water movement. Their tube is not built of sand, debris or slime as has been thought for a very long time. Instead, it is almost entirely made up of nematocysts of a special type called ptychocyst (Mariscal et al., 1977). Little is know about their reproduction, yet fission of the body, budding, production of sperm and eggs resulting in planktonic larvae, and live birth have been documented in various species. Since tube anemones are burrowing animals they should be provided with an inert container in the aquarium filled with sand/gravel and sized to easily fit the length and width of their tube. Some species are night animals and only expand their tentacles in the dark. Their outer longer tentacles are used to catch food and transfer it to the shorter inner tentacles, which then transfer the catch to the mouth. Tube anemones should be fed very small pieces of fish, clam, mussel, and/or squid and frequency depends upon their species. Keep in mind the tube anemone has the ability to capture and eat small fish and shrimp, therefore, some thought must be given before placing it into a well-stocked aquarium. It is better kept in an aquarium dedicated to its needs.
Back to Animal Library Index...