Velvet Nudibranch: The Specialized Flatworm Predator
The Velvet Nudibranch (Chelidonura varians), often referred to as the Blue Velvet Headshield Slug or Flatworm Eating Slug, is a strikingly beautiful and highly specialized marine invertebrate. Despite its common name, it is a Headshield Slug (Order Cephalaspidea), not a true Nudibranch (Order Nudibranchia).
This slug is famous in the aquarium trade for its stunning coloration—a deep black body outlined by vivid, electric blue margins. It has a characteristic ‘hammerhead’ shape and two unequal posterior tails. The Velvet Nudibranch is typically introduced into aquariums for one primary purpose: as a natural, highly effective predator of nuisance flatworms.
| Species | Chelidonura varians |
|---|---|
| Common Names | Blue Velvet Headshield Slug, Flatworm Eating Slug |
| Order | Cephalaspidea |
| Body Color | Deep black with electric blue margins |
| Shape | Hammerhead with two unequal posterior tails |
| Primary Function in Aquarium | Predation of nuisance flatworms |
FAQ
What is the difference between a Velvet Nudibranch and a true Nudibranch?
The Velvet Nudibranch (Chelidonura varians) is a Headshield Slug (Order Cephalaspidea), not a true Nudibranch (Order Nudibranchia). It shares the name due to appearance but belongs to a different taxonomic group.
Does the Velvet Nudibranch eat other aquarium inhabitants?
No, the Velvet Nudibranch is specifically adapted to prey on flatworms and does not pose a threat to fish, corals, or other invertebrates in a balanced aquarium.
How long does it take for a Velvet Nudibranch to start controlling flatworm populations?
It typically takes 2 to 4 weeks for the Velvet Nudibranch to establish itself and begin actively hunting flatworms, depending on tank conditions and flatworm density.
Cameron Rampling –
I introduced the Velvet Nudibranch to my reef tank after a flatworm infestation. Within three weeks, I noticed a significant reduction in flatworm numbers. It’s calm, doesn’t interfere with other species, and looks stunning with its blue margins. A must-have for any aquarium with flatworm issues.
Alan Roberts –
The slug arrived healthy and quickly started hunting flatworms. I was worried about it eating corals, but it only targets flatworms. The color is vibrant and it adds a unique visual element to the tank. Very effective and peaceful.
Vanessa Ellison –
It works well for flatworm control, but it takes a few weeks to become active. I had to keep the tank stable with proper water parameters. Once established, it’s a reliable predator and looks beautiful.
Penelope Hunter –
After a bad flatworm outbreak, I added the Velvet Nudibranch. It has completely eliminated the problem without harming any other inhabitants. The blue color stands out and it’s a great addition to the tank’s aesthetic.