Carpet anemones is a sub-group or classification of sea anemones from the genus Stichodactyla. They are fascinating marine creatures characterized by their large flattened bodies and short carpet-like tentacles.
Carpet anemones are known for their beauty, large sizes and their close association with some clownfish species. They are best suited for advanced marine aquarists since it can be quite challenging to maintain in the aquarium, in addition to its low success rate, hence, we advise beginners to stay away.
In this article, we will be talking extensively about the Carpet anemones; how to care for them and choosing suitable tankmates.
Quick Notes about Carpet Anemones
|Tank size (minimum)
|50 gallons (~200 liters)
|Moderate to high
|Moderate to high
|25 – 28°C (~75°F – 83°F)
|SG = 1.023 – 1.025
|8.1 – 8.4
|8 – 12
|Less than 10 ppm
|Lots of variations of green, blue, purple, yellow, grey, or even pink
Varieties of Carpet anemones
There are three varieties or species of carpet anemones commonly found in the hobby, they belong to the genus Stichodactyla and includes:
- Stichodactyla gigantea
- Stichodactyla haddoni
- Stichodactyla mertensii
Stichodactyla gigantea: This species is commonly known as the Giant carpet anemone. Its features include: a deeply-folded oral disc, slightly tapering tentacles that vibrate constantly (short) but they are longer than that of Stichodactyla haddoni, extremely sticky and often slightly pointed at the tips.
Usually, a huge part of the disc is free form tentacles and it can grow up to 50 cm (20 inches).
Stichodactyla gigantea can appear in a variety of colors, commonly brown or greenish, rarely striking purple or pink, deep blue or dark green.
Its geographical distribution is in the Indo-Pacific region (Micronesia to the Red Sea, and Australia to the Ryukyu Islands), it resides on shallow waters and seagrass beds or sand flats around 1 to 20 m (~3 to 60 feet) deep.
Stichodactyla haddoni: Commonly known as Haddon’s sea anemone or Saddle anemone. Stichodactyla haddoni has very small bulbous tentacles that look like little beads that cover the surface. The oral disc diameter is between 50 cm – 80 cm (20 – 31 inches), tentacle-free oral area of 10-20mm (0.4 – 0.8 inches).
Presence of a small, non-adhesive verrucae on uppermost column which is of the same color as the column or light purple sometimes. The tentacles are longer and distinctively shaped; the tentacle ends can be green, yellow, grey, or pink, the other species lack robust exocoelic tentacles.
Geographical distribution is in the tropical and subtropical waters of the Indo-Pacific area from Fiji Islands to Mauritius, Australia to the Ryukyu Islands. This species is found singly at depths of 4 to 40 m (12 to 120 feet).
Stichodactyla mertensii: Also known as Mertens’ carpet sea anemone. This species holds the record for largest oral disc diameter being over 3 feet: an oral disc of 39 inches (1 meter) or more. It has a tan to white column with longitudinal rows of verrucae pigmented orange (appears purplish at depth), short tentacles less than an inch and non-sticky.
This species has a broad oral disc that appears to be more ovoid than circular and lies smoothly over substratum. Tentacles are of uniform diameter, blunt-ended or pointed in some cases.
Stichodactyla mertensii can be found living on hard surfaces; rocky or coral substrate and is common in Indo-Pacific areas (Micronesia and Melanesia, and Australia to the Ryukyu Islands. Despite their huge size, these anemones are usually found at 1 to 20 m (~3 to 60 feet) deep.
In general, these species have fairly broad ranges going from the South Pacific west to the coast of Africa with Stichodactyla gigantea and Stichodactyla haddoni extending into the Red Sea. All three species can be found in Australia and north to the Ryukyu Islands.
Behavior of Carpet anemones
Carpet anemones are very conscious of their environment and they can be quite picky about where they live. They barely move about in a tank unless they are not pleased with where you placed them, if that is the case, they will crawl around in search of a better / convenient spot.
This is quite risky, as many immobile tankmates they may come in contact with or cover up can be killed in the process. Try as much as possible to get the positioning right in the first instance. It is best to put a baserock and the anemone into an aquarium first, let it settle in where it wants to, then you can start adding other necessary things. Once settled, there are high chances of anemones staying put indefinitely.
When it comes to predatory instincts, the carpet anemones are adequately equipped. Their tentacles are covered by numerous stinging cells called cnidocytes, and these cells fire tiny harpoon-like structures into the prey once contact is made.
These harpoon-like structures enables the anemone to clutch onto a prey and also inject toxins into the victim to immobilize or kill it.
It is worthy to mention that they don’t sting everything they come in contact with, their stinging cells do not react to random brushes with rocks, sand and other non-fleshy things in their surroundings and additionally, they do not react with certain clownfish either as they do not consider it as a prey.
Tank Requirements / Water Parameters
Carpet anemones need a large, stable and established reef tank to dwell comfortably. These species are not suited for nano tanks due to their remarkable sizes and they take up a great deal of space in the tank.
The minimum tank size for housing carpet anemones should be 50 gallons (200 liters), more capacity is even better as they need lots of space, especially, in case of Stichodactyla haddoni and Stichodactyla mertensii.
Water type, Temperature, Hardness, and pH:
Temperature: The recommended temperature range should be between 25 and 28 °C (75 – 82 °F). Radical temperature shifts should be avoided as they can harm the carpet anemones and clownfish.
pH: Optimal pH conditions should be maintained at all times, this set-up needs stable pH in the range of 8.1 – 8.4. This should be adequately monitored and adjusted using testing kits and frequent manual dosing of calcium and pH buffer additives.
Hardness: Water hardness should be between 8 – 12 dKH.
Carpet anemones house symbiotic algae known as zooxanthellae in their tissues, just like reef-dwelling corals, and they are highly dependent on strong lighting to stay healthy. VHO, compact fluorescent, and T5 high output lighting, or metal halide lamps should suffice, depending on the depth of the aquarium.
5000-10000k temperature range is recommended and should be maintained at all times. The essence of intense lighting is to enable zooxanthellae perform photosynthesis and in turn produce simple sugars that the anemones can utilize for food.
Turbulent water flow needs to be present in sufficient turnover volume to lightly ruffle the edges of the Carpet anemones. It should not be excessive to avoid pushing the anemone all over the place.
Living Arrangements of Carpet Anemones
The three species do not dwell in the same type of place and as such will prefer their own particular living arrangements.
Stichodactyla haddoni lives in deep sand with its base dug-in deeply, which allows it to retract its body into the sand and retreat if bothered. Therefore, it is best to place a specimen on a deep sandbed where it will feel at home.
Worthy to mention that they are occasionally found on hard substrates too, and you may find one hanging onto rocks even if initially placed on sand substrate.
Stichodactyla gigantea is normally found with its base clutching onto something solid buried in sand so that much of the base is buried. They can as well be found attached to hard substrates at the surface.
The best way of placing the gigantea is to dig a hole in the sand and place their base in the hole, then fill in around the base and place a piece of liverock next to it.
Stichodactyla mertensii typically lives on hard substrates with its base attached in a cervice or hole and its disc held close to the surrounding rocks.
Therefore it is best to arrange the rocks in a way that allows it to replicate same in the tank. Place a specimen with its base in the hole and allow it to make an attachment.
Feeding Carpet Anemones
Carpet anemones are predators. They are capable of capturing prey of suitable sizes (small invertebrates, fry or juvenile fish) that comes within the reach of their tentacles and digesting it with their nematocysts.
They feed internally through photosynthesis of its symbiotic algae – zooxanthellae and also on planktonic matter conveyed by the water currents. Another source of nutrients is from the wastes of their symbiotic fish.
Carpet anemones can also devour fleshy raw meals, these consist of brine shrimp, clam meat, whole shrimps, small fish like guppies, goldfish, etc.
However, you shouldn’t overfeed them if you don’t desire a substantial increase in their sizes.
- Feed your Carpet anemones 2 – 4 times a week at most.
- You will need to target feed them.
Breeding and Reproduction
Unfortunately, it is almost impossible to breed Stichodactyla sp.in captivity.
In nature, these anemones can breed by sexual and asexual means.
- Sexual reproduction involves sex cells or fertilization of released eggs in the water column. It is really hard to see them spawning because it also depends on the moon cycle. Fertilized eggs produce planula larvae that settles on the sea floor and grows into a new anemone.
- Asexual reproduction requires only one parent which splits in half from the foot or mouth to form a copy of itself (cloning). Professional aquarists cut them in half and let them heal for a month or two.
Please, DO NOT do that in your home aquarium! Without proper technic you will kill the anemone.
Carpet Anemones and Suitable Tankmates
Like all sea anemones, the three carpet anemones have a symbiotic or mutualistic relationship with anemonefish otherwise known as Clownfish. The symbiont (clownfish) recieves protection from predators provided by the anemones stinging cells, and the anemone utilises the nutrients present in its faeces.
Likewise, Stichodactyla gigantea hosts A. akindynos. A. bicinctus, A. clarkii, A. ocellaris, A. percula, A. perideraion, and A. Rubrocintus.
While Stichodactyla mertensii hosts A. akallopisos, A. akindynos, A. allardi, A. chrysogaster, A. chrysopterus, A. clarkii, A. fuscocaudatus, A. latifasciatus, A. leucokranos, A. ocellaris, A. sandaracrinos, A. tricintus.
These aforementioned species of clownfish can be paired with the various carpet anemones, however, the underlying problem with these matchups is that there are instances whereby the clowns ignores a supposedly compatible carpet; even when it was the only anemone in the tank.
The Amphiprion clarkii is the most compatible clown as all three anemones can host it, and it rarely rejects a carpet anemone nor does an anemone reject it.
Another compatible tankmates are the Periclemenes (anemone shrimp) and Thor amboinensis (The ‘Sexy’ Shrimp). They also exhibit a symbiotic relationship with carpet anemones, presumably for protection from predators. These are a small shrimp species. The first ones can grow up to 5 cm (2 inches) in length. The Sexy shrimp is way smaller – up to 2 cm (~0.8 inches).
Anemone shrimp are great additions to a carpet anemone dedicated tank, however, they should not be used in combination with other symbionts eg. Clownfish.
The last option, that comes to my mind, is Porcelain Anemone crab (Neopetrolisthes maculatus).
These crabs have been encountered in association with several different genera of sea anemones, including Stichodactyla spp.
Problems Associated With Carpet Anemones
- The carpet anemones are likely to shrink and eventually die off if you don’t provide them with strong lighting to enable them photosynthesize and stay healthy. This can also occur when you are underfeeding them.
- These creatures are prone to shipping stress and bacterial infections during transit, many hobbyists recommend quarantining it and treating with antibiotics such as Ciprofloxacin or Septra for a minimum of one week before acclimating it to the main tank.
- Carpet anemones are predators, and as such, they will devour aquatic species that do not have a symbiotic relationship with it. These include cleaner shrimp (Peppermint shrimp, Red Fire shrimp, Skunk Cleaner Shrimp), snails, crabs, bottom-dwelling fish species as well as non-compatible anemonefish (clownfish). Adhere strictly to the matching guide we provided earlier.
- Poor survival rate is a major concern over keeping anemones in the aquarium. To help minimize this, you are to provide strong lighting, ensure that ammonia and nitrite are close to zero. In fact, carpet anemones are highly sensitive to unstable water parameters, therefore water quality should be very good at all times.
Buying Carpet Anemones
If you are keen on achieving success in the aquarium care of Carpet anemones then you should ensure that you purchase a healthy specimen. Here are some of the things to look out for:
- A healthy Carpet anemone should have a closed mouth; an open oral cavity with the guts sticking out is definitely not a good sign.
- Watch out for signs of bleaching. Bleaching occurs when an anemone is exposed to prolonged extreme high temperature conditions. This results in the expulsion of the anemone’s complement of zooxanthellae, which eventually leaves the host looking pale. You should avoid purchasing such specimen.
- Ensure that the animal doesn’t have any severe injuries – cuts and tears on their base. Such injuries can lead to an infection or even worse, death.
- When it comes to Carpet anemones; an attachment to surfaces is a sign of good health. A healthy specimen should be firmly attached to something in the shop e.g. rock, shell, glass, etc.
The issues of high mortality rate and difficulty in caring for carpet anemones make many aquarists shy away from keeping carpet anemones in their tanks. These animal species are definitely suited for advanced aquarists who have gained a lot of experience in the hobby and are willing to dedicate time to maintain them.
In addition, carpet anemones will introduce a whole new aesthetical display in your tank, so it is worth the commitment. Finally, bear in mind that acquiring a healthy specimen influences its long-term survival positively.
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