Jorunna funebris - Common Slug

Jorunna funebris is a shell-less marine gastropod belonging to the family Discodorididae. Its white or pale-grey body is covered with small papillae that create a soft, velvety appearance. Large black spots or rings contrast strongly with the pale background.

Two black-tipped rhinophores are positioned at the front of the body, while a circular plume of feather-like gills is located near the rear. Both structures can be retracted when the animal is disturbed.

The highly specialised diet makes this species extremely difficult to maintain in an ordinary reef aquarium.

Key features

• Striking black-and-white nudibranch
• Scientific name: Jorunna funebris
• Family: Discodorididae
• White or pale-grey velvety body
• Large black spots or rings
• Black-tipped rhinophores
• Feather-like dorsal gill plume
• Native to Indo-Pacific reef environments
• Completely peaceful
• Specialised sponge feeder
• Does not accept ordinary aquarium food
• Does not graze algae
• Not a clean-up-crew animal
• Reef safe only with caution
• May consume ornamental sponges
• Requires a continuous supply of the correct sponge
• Sensitive to unstable water conditions
• Sensitive to copper and medications
• Must be protected from pump intakes
• Aquarium must be escape resistant
• Recommended only for experienced marine aquarists

Care information

• Adult size: commonly approximately 5–7 cm
• Diet: selected sponge species
• Temperament: peaceful
• Reef compatibility: with caution
• Care level: extremely difficult
• Origin: Red Sea and East Africa through Indonesia, Australia and the western Pacific
• Recommended system: specialised aquarium designed around the required food sponge

Suggested water conditions

• Temperature: approximately 22–26 °C
• Specific gravity: approximately 1.023–1.026
• pH: approximately 8.1–8.4
• Alkalinity: approximately 7–11 dKH
• Ammonia: 0 mg/l
• Nitrite: 0 mg/l
• Flow: moderate and indirect
• Oxygenation: high

Feeding

Before purchase, identify the sponge that the individual has been eating. Maintain a continuous supply of the same sponge and replace it before the available growth is completely consumed.

Ordinary fish foods, frozen foods, coral powders, phytoplankton and algae sheets do not provide an adequate substitute.

Introduction

1. Confirm that the required sponge is available.
2. Protect all pump and overflow intakes.
3. Dim the aquarium lighting.
4. Equalise the transport-water temperature.
5. Acclimate gradually to salinity and water chemistry.
6. Avoid unnecessary exposure to air.
7. Do not handle the animal with bare hands.
8. Transfer it underwater in a small container.
9. Place it directly beside the identified food sponge.
10. Temporarily reduce strong water flow.
11. Confirm that the animal attaches to the substrate.
12. Monitor feeding and body condition closely.
13. Avoid all copper-based medications.