Common Bladderwort vs common grey sea slug

Utricularia vulgaris compared with Aeolidia papillosa

Key Differences

• Common Bladderwort is Near Threatened while common grey sea slug is Least Concern.

Taxonomic Classification

Rank	Common Bladderwort	common grey sea slug
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Mollusca (Mollusks)
Class	Magnoliopsida (Dicots)	Gastropoda (Gastropoda)
Order	Lamiales (Lamiales)	Nudibranchia (Nudibranchia)
Family	Lentibulariaceae	Aeolidiidae
Genus	Utricularia	Aeolidia
Species	Utricularia vulgaris	Aeolidia papillosa

Conservation Status

Common Bladderwort

NT — Near Threatened

common grey sea slug

LC — Least Concern

Physical Characteristics

Attribute	Common Bladderwort	common grey sea slug
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Bladderwort

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Distributed across Belgium, Denmark, Norway, Sweden, and United States. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

common grey sea slug

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Chile, Denmark, Norway, and Sweden.

Common Bladderwort

The common bladderwort (<em>Utricularia vulgaris</em>) is a carnivorous aquatic plant belonging to the family Lentibulariaceae. It is classified as Near Threatened on the IUCN Red List, reflecting population declines linked to habitat loss and water quality degradation. The species has been recorded across diverse terrestrial tropical to temperate habitats in Belgium, Denmark, Norway, Sweden, and the United States. <em>Utricularia vulgaris</em> is typically found in slow-moving or still freshwater bodies such as ponds, lakes, ditches, and marshes. It is rootless and free-floating, with finely divided submerged stems bearing numerous small bladder-like traps that capture zooplankton, small aquatic invertebrates, and even mosquito larvae through a rapid suction mechanism. The plant produces yellow snapdragon-like flowers on emergent stems above the water surface during summer. Its carnivorous strategy allows it to supplement nutrients in nutrient-poor aquatic environments. Biological traits of this species remain poorly documented in the scientific literature.

common grey sea slug

<em>Aeolidia papillosa</em>, commonly known as the common grey sea slug, is a nudibranch mollusc belonging to the genus Aeolidia within the family Aeolidiidae. Despite the species name referencing terrestrial and aquatic habitats including forests and freshwater, <em>Aeolidia papillosa</em> is primarily a marine organism. Its range includes Belgium, Chile, Denmark, Norway, and Sweden, indicating a distribution across the North Atlantic and into South American waters. Common grey sea slug is assessed as Least Concern on the IUCN Red List. The species is typically found in intertidal and subtidal zones, where it preys on sea anemones and stores stinging cells from its prey in its dorsal cerata for defense. Biological traits of this species remain poorly documented in the scientific literature.

Shared Countries

Both species can be found in 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden