Small Rock Anemone

Glass Rose Anemone, Trumpet Anemone

Small Rock Anemone, Aiptasia diaphana, Glass Rose Anemone, Trumpet AnemoneAiptasia diaphanaPhoto © Animal-World, Courtesy David Brough

Quick as a whip, the Small Rock Anemone will retract into its hole or crevice if it feels threatened!

Don't be fooled by this quick maneuver, even though a Small Rock Anemone Aiptasia diaphana is fast at disappearing if disturbed, that's just one of its fast tricks. This pretty rock anemone, also known as the Glass Rose Anemone, is very fast at reproducing and can quickly overrun its environment. Small Aiptasia anemones don't have a very good reputation with saltwater hobbyists, because they can reach plague proportions in a saltwater aquarium or a reef tank.

All Aiptasia anemones have strong stings, and don't "play nice" with other corals and fish. They use venomous cells, nematocysts found in their tentacles, to sting corals and fish. They are very hard to get rid of and have been known to take over a reef aquarium by quickly reproducing while stinging and killing other tank invertebrates.

Corals and other anemones are the invertebrates most affected by Aiptasia pests. Unless you are keeping Small Rock Anemones in a refugium to help control nutrients, they need to be removed as soon as possible. Once Aiptasia gets a foothold, manual removal to keep populations in check, may very well become an ongoing activity.

Despite a bad reputation in the saltwater aquarium industry, the Small Rock Anemone does have redeeming qualities in the scientific world. It is used extensively for studies on growth due to its re-generation properties. It is also being considered for use in medical treatments. A method of using its stinging cells in skin creams to deliver insulin to diabetics in a needle-free way is being explored. Other Aiptasia species being used in various types of research include the Glass Anemone Aiptasia pulchella, and the Brown Glass Anemone Aiptasia pallida.


For more about the types of Sea Anemone Species, see:
Sea Anemone - Tube Anemone

Small Rock Anemone, Aiptasia diaphana

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Another pest anemone that comes in brown or pinkish

This is yet another anemone that is considered an undesirable addition to a reef tank! The Small Rock Anemone, also called the Rose Glass Anemone is slightly different from the standard Aiptasia in that it has more color, being brown to a pinkish brown instead of clear or gray. Whatever color it is, it needs to go! When you see one, do your best to get rid of it before it reproduces!

Small Rock Anemone - Quick Aquarium Care
  • Minimum Tank Size: 1 gal (4 L)
  • Aquarist Experience Level: Beginner
  • Temperament: Aggressive
  • Temperature: 68.0 to 86.0° F (20.0 to 30.0° C)
  • Size of organism - inches: 1.2 inches (3.05 cm)
  • Diet Type: Carnivore
  • Suitable for Nano Tank: Yes

Habitat: Distribution / Background

Sea Anemone Facts: The Small Rock Anemone Aiptasia diaphana was described by Rapp in 1829. The Aiptasia genus is a member of the Aiptasiidae family, and this genus contains 17 species. Some other common names it is known by are the Glass Rose Anemone and the Trumpet Anemone. Aiptasia diaphana is not on the IUCN Red List for endangered species.

Where are Sea Anemones Found: This anemone has a very broad range. It is found in the Mediterranean and Canary Islands, Bali, Indo Pacific, Indonesia, Kenya, Philippines and the Red Sea.

Sea Anemone Habitat: Aiptasia anemones are found in shallow waters along protected coasts and along intertidal rocky shorelines. They are found alone attached to rubble, live rock, dead corals, and other hard substrates.They will also form dense colonies in areas of shallow water, sometimes so dense they look like solid sheets. They occur in deep water too, where there is good tidal action. They generally eat zooplankton, but will always accept other food particles.

Sea Anemone Species: There are 17 species in the Aiptasia Genus. General common names all the various Aiptasia anemones are known by are Aiptasia, Glass Anemone, Glassrose Anemone, Rock Anemone, Devil's Plague, Aiptasia Anemone, Pest Anemone, and sometimes by this misspelling, Aptasia.

  • Scientific Name: Aiptasia diaphana
  • IUCN Red List: NE - Not Evaluated or not listed


Appearance of a Sea Anemone: The Trumpet Anemones are somewhat translucent and generally occur in a brownish or pink to reddish color with lighter tentacle tips. Their coloring comes from an algae called zooxanthellae living in its tissues.

Aiptasia diaphana are quite small, only reaching about 1.2" (3 cm) tall. Their body form is the polyp. It is composed of an elongated column with an oral disc on top that has a mouth in the center. There are elongated tapering tentacles positioned in narrow rings on the outer margin of the oral disc. If it feels threatened, quick as a whip, this anemone will rapidly retract its tentacles, becoming a very small ball, and it will retract into its hole or crevice.

How do glass anemones move?: The Glass Rose Anemone has a pedal disc or 'foot' with which it attaches to the substrate. If tank conditions are not ideal they will use their "foot" to move along the substrate. Aiptasia anemones do this by contracting the circular muscles of the foot and pushing forward, or they may crawl on their side, moving about 4 cm per hour. Often Aiptasia will simply opt to disconnect and float around, or swim by moving in a spiral motion, until they find a new spot to adhere too.

Sea Anemones Life Cycles: It is unknown how long Aiptasia can live, but they do reproduce quickly. Mature specimens can produce dozens of juveniles in a single day if they have plenty of nutrients.

  • Size of organism - inches: 1.2 inches (3.05 cm)
  • Lifespan: - It is unknown how long Aiptasia can live.

Difficulty of Care

Sea Anemone Care: Some aquarists use aiptasia in their refugiums to take out nutrients from the water. Small Rock Anemones are easy to care for and they are quite hardy and durable. They have the ability to reproduce rapidly in saltwater aquariums where there are plenty of nutrients and good lighting.

Small Rock Anemones can reach plague proportions in captivity. In some aquariums they will reproduce faster than in others, but the exact reason is unknown. They do seem to reproduce faster in environments high in nutrients and detritus. This anemone as well as any species of Aiptasia is generally regarded as a pest. They can be difficult to control and/or eliminate once they get a foothold.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

What Do Sea Anemones Eat: The Trumpet Anemone is a carnivore. In the wild Aiptasia derive nutrition from their symbiotic algae, zooxanthellae, as well as from the water around them. They use their tentacles to capture organic matter that floats by, then insert the food into their mouths for ingestion. They generally eat zooplankton, but will always accept other food particles.

  • Diet Type: Carnivore
  • Meaty Food: All of Diet - In the wild Aiptasia derive nutrition from their symbiotic algae, zooxanthellae, as well as from the water around them. They use their tentacles to capture organic matter that floats by, then insert the food into their mouths for ingestion.
  • Feeding Frequency: Seldom

Aquarium Care

Water changes of 10% bi-monthly or 20% a month are typical for most anemones, but with Aiptasia, the more nutrients you have the happier it will be. They will flourish in poor water quality environments that are rich in organic nutrients.

  • Water Changes: Bi-weekly

Aquarium Setup

Using aiptasia in refugiums to take out nutrients can be effective, yet it can also be risky if any part of an aiptasia migrates to the main tank through the filtration. The typical reef environment is best for these anemones. Like most anemone species, they need live rock or some other solid material they can attach to. In a refugium use screening to prevent free floating aiptasia from migrating to your main tank. Be sure to have all of your pumps covered. Most good quality pumps have guards on them.

  • Minimum Tank Size: 1 gal (4 L)
  • Suitable for Nano Tank: Yes
  • Live Rock Requirement: Typical Amount
  • Substrate Type: Any
  • Lighting Needs: Any - They will thrive in bright light, but even under poor lighting aiptasia anemones will survive.
  • Temperature: 68.0 to 86.0° F (20.0 to 30.0° C)
  • Specific gravity: 1.023-1.025 SG
  • Water Movement: Weak - Low to Moderate.
  • Water Region: Bottom

Social Behaviors

The Small rock Anemones are aggressive anemones that have strong stings that can harm, and even kill other corals and fish. Saltwater hobbyists don't purchase these anemones, rather they are acquired accidentally and they are able to out compete other species in the reef tank. When disturbed they eject dangerous white stinging threads, or acontia. By using venomous cells or nematocysts found in their tentacles, they sting and push other inhabitants away from their "turf".

  • Venomous: Yes
  • Temperament: Aggressive
  • Compatible with:
    • Same species - conspecifics: Yes
    • Anemones: Threat
    • Mushroom Anemones - Corallimorphs: Threat
    • Leather Corals: Threat
    • Zoanthids - Button Polyps, Sea Mats: Threat
    • Stony Corals: Threat - is aggressive
    • Soft Corals: Threat - is aggressive

Sex: Sexual differences

Studies of A. pallida and A. pulchella have determined that Aiptasia individuals are dioecious, meaning that individuals are of separate sexes. However, no sexual difference in appearance is known.

Breeding / Reproduction

Propagating aiptasia anemones is fairly easy, just cut a piece off and it will grow. Anemones in general can multiply by sexual and asexual means. Aiptasia will multiply asexually by fission, which is where a tiny bit of tissue detached from the foot quickly develops into a new and complete anemone.

Aiptasia anemones will tolerate their own "clones", and these anemones are very prolific. This is why it is very difficult to physically remove these anemones from a rock. Any remaining tissues quickly multiply into to new specimens. Sexual reproduction has not been described for the species.

  • Ease of Breeding: Easy

Ailments / Diseases

Problems for the Small Rock Anemone are pretty minimal unless your lighting, water movement, feeding and water quality are low. Then your anemone will detach to look for "better conditions." With better conditions, they can quickly multiply, and having a quickly expanding population of Aiptasia then becomes the problem.

Regular and time consuming manual removal is often required so that an aquarium is not overrun by dense populations of Aiptasia. There are various ways to reduce and control aiptasia populations. Sea anemone predators provide a natural, biological method of controlling and possibly eliminating Aiptasia anemones. Other methods include chemical removal and the more risky method of physical removal. There are important considerations when using either of these two methods.

For information on Aiptasia removal and control, see: Aiptasia Pests - Getting Rid of Glass Anemones.


Buy A Sea Anemone: Saltwater aquarists don't usually buy Small Rock Anemones, but Aiptasia is available alive from supply companies for research and scientific study. Aquarists generally acquire them as hitchhikers, arriving with live rock or attached to the base of corals..


Author: Clarice Brough CFS
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