family Diadumenidae
Found attached to hard surfaces in the Seagrass Meadow, this small sessile predator extends rings of stinging tentacles to capture zooplankton and small crustaceans from the water column and reproduces by clonal fission to spread gradually across available substrate.
The Sea Anemone in miniBIOTA's Seagrass Meadow is a small sessile predator in family Diadumenidae, identified to family level only; exact genus and species remain unresolved. It arrived on November 11, 2024 as a hitchhiker on oysters and has since established a colony of approximately 15 individuals through clonal fission. A March 21, 2026 observation captured the anemone actively consuming an Eelgrass Isopod, the first documented feeding event in miniBIOTA. Cloning is confirmed; some clones fail and shrink, and the population appears to have reached a natural ceiling. Population status is Established.
Diadumenidae anemones, particularly members of the genus Diadumene, are found in coastal marine and estuarine habitats worldwide. Diadumene lineata, the orange-striped green anemone, is cosmopolitan: it originated in Pacific coastal Asia and has spread globally through shipping, aquaculture, and the live marine trade. It is well established in Florida's coastal marine habitats and is frequently found attached to oyster shells, dock pilings, aquarium glass, and hard substrate in shallow marine systems. It tolerates a wide range of salinity and temperature conditions, which explains its success as a global colonizer. If the miniBIOTA individual is D. lineata, the November 2024 arrival on oyster shells follows exactly the typical pattern for this species.
Diadumenidae anemones are sessile; they attach to hard substrate and remain in place. They are found on glass, rock, shell, plastic, pipe, and other stable surfaces in shallow marine and intertidal zones. They extend their column and tentacles into the water column to feed and retract tightly when disturbed. In miniBIOTA, anemones occupy hard surfaces in the Seagrass Meadow and have spread from the original oyster attachment point to colonize nearby substrate through clonal fission.
Sea anemones are active predators. They capture prey using stinging cells (nematocysts) embedded in their tentacles. When a small animal makes contact with an extended tentacle, nematocysts discharge and immobilize it; the prey is then drawn into the central oral disc and ingested. The diet of small Diadumenidae anemones typically includes zooplankton, copepods, amphipods, larvae, and small crustaceans small enough to be captured and restrained by the tentacles. In miniBIOTA, a direct feeding event was observed on March 21, 2026, when a sea anemone was captured on video actively consuming an Eelgrass Isopod, the first documented feeding event for this species in the system.
Diadumenidae anemones reproduce primarily through asexual clonal fission. An individual anemone splits along its base, producing a new genetically identical individual. This process allows rapid local colonization of substrate without requiring mates or external fertilization. In miniBIOTA, clonal reproduction is confirmed; the population has grown from the original hitchhiker introduction to approximately 15 individuals. Some clones are unsuccessful: they fail to establish, shrink, and wither. The population appears to have reached a natural ceiling under current system conditions, consistent with space or resource limitation.
Sexual reproduction is possible in Diadumenidae anemones and involves release of gametes into the water column, but no sexual reproduction has been observed or is suspected in miniBIOTA. The closed saltwater system and limited population likely make sexual reproduction unlikely unless conditions change significantly.
Diadumene anemones are notably tolerant of variable environmental conditions. D. lineata in particular is documented to tolerate wide salinity swings (from near-freshwater to hypersaline), temperature variation from cold temperate to subtropical conditions, and periodic oxygen depletion. This environmental tolerance is a major reason for its global spread. No miniBIOTA-specific tolerance measurements have been taken.
Sea anemones function as sessile predators in the Seagrass Meadow food web. By capturing zooplankton, larvae, and small crustaceans with stinging tentacles, they intercept small mobile animals that would otherwise pass through the system. The March 2026 feeding event on an Eelgrass Isopod demonstrates active predation on mobile invertebrate prey larger than typical zooplankton targets. This places the Sea Anemone at a secondary consumer level, connecting the zooplankton and small crustacean community to a sessile predator anchored to the substrate.
The colony of 15 individuals distributed across Seagrass Meadow substrate represents a diffuse but consistent predation pressure on small animals moving through the water column. Clonal reproduction allows the colony to expand without external recruitment, making the population self-sustaining under current conditions.
No confirmed predators are known in miniBIOTA. In natural settings, anemones are eaten by nudibranch mollusks and some specialized fish; none have been confirmed in miniBIOTA's saltwater zone. No symbiotic relationships have been documented, though anemones in natural settings can host symbiotic algae (zooxanthellae) or commensal animals.
Sea anemones arrived at miniBIOTA on November 11, 2024, attached to oyster shells introduced to the Seagrass Meadow. Introduction method: Hitchhiker. No deliberate seeding; the anemones were incidental arrivals.
Sea anemones arrived as hitchhikers on oysters in November 2024 and established a colony of approximately 15 individuals through clonal fission. Cloning is confirmed; some unsuccessful clones shrink and wither. A population ceiling appears to have been reached, likely reflecting space or resource constraints in the Seagrass Meadow. Active predation on an Eelgrass Isopod confirmed March 21, 2026. Colony still on record as of June 10, 2026.
Sessile predator using nematocyst-bearing tentacles to capture zooplankton, larvae, and small crustaceans. Direct predation on an Eelgrass Isopod observed March 21, 2026 (video), the first documented feeding event in miniBIOTA.
Diadumenidae anemones, particularly Diadumene lineata, are noted for exceptional tolerance of salinity variation, temperature swings, and periodic hypoxia, which explains their success as global colonizers. No miniBIOTA-specific tolerance measurements on record.
Clonal fission is confirmed in miniBIOTA; the colony has expanded from the original hitchhiker introduction to approximately 15 individuals. Some clones fail to establish and shrink. Population appears to have reached a ceiling. Sexual reproduction has not been observed and is unlikely under current closed-system conditions.
Sessile predator intercepting zooplankton, larvae, and small crustaceans in the Seagrass Meadow water column. Colony of approximately 15 individuals provides diffuse but consistent predation pressure. No symbiotic relationships documented in miniBIOTA.
Follow this species across the habitats where it currently appears in the miniBIOTA biosphere.
