Knobby Sea Rod Care Guide
Eunicea succinea, the knobby sea rod, is a hardy Caribbean photosynthetic gorgonian with thick stems and sparse branches for high-flow marine tanks.
Compiled by Aquairi from published sources · Published · Updated
Overview
Eunicea succinea is a Caribbean photosynthetic gorgonian, an octocoral known as the knobby sea rod. It forms thick stems with sparse branching and, like other gorgonians, is a colony of polyps each bearing eight pinnate tentacles. It is regarded as relatively hardy in the aquarium.
Taxonomy
- Family: Plexauridae
- Genus: Eunicea
- Scientific name: Eunicea succinea (Pallas, 1766)
- Class: Octocorallia; Order: Malacalcyonacea
- WoRMS AphiaID: 283262 (accepted)
Habitat and biology
The species occurs on Caribbean reefs. It is zooxanthellate, relying largely on photosynthetic symbionts while also capturing plankton with its polyps. As a flexible branched gorgonian, it favours water with strong currents.
Aquarium care
Eunicea succinea is a passive, reef-, shrimp- and fish-safe coral suited to intermediate keepers. Its photosynthetic biology means strong light is not required, but it needs high flow to remain clean. It is best added to an established tank of at least about three months.
Tank requirements
- Temperature: 24-26 °C (75-79 °F)
- Salinity: 1.024-1.026 SG
- pH: 8.1-8.4
- Alkalinity (dKH): 8-11
- Calcium: 380-450 ppm; Magnesium: 1280-1350 ppm
- Nitrate: ≤15 ppm; Phosphate: ≤0.1 ppm
- Lighting: 75-175 PAR (medium); Flow: high
- Growth rate: 0.3-0.8 cm per month (tree-like)
Feeding
In addition to photosynthesis, supplemental amino acids and phytoplankton support the colony, which filters these foods from the water column.
Eunicea succinea (Knobby Sea Rod) Propagation Guide
Overview
Eunicea succinea is a gorgonian-type octocoral in the family Plexauridae, a Caribbean genus established by Lamouroux in 1816. These branched octocorals typically have knobby protuberances from which the polyps protrude, are often stiffened by purple sclerites, and the growth of these corals is rapid, so they can be kept in a reef aquarium. As a shallow-water photosynthetic gorgonian it relies heavily on light.
Reproductive Mode
Octocorals follow a life cycle with a motile planktonic planula larva and a later sessile phase, and their gonads lie near the base of each mesentery, so wild reproduction proceeds through gamete release and a larval stage. In aquaria the rapid-growing Eunicea is multiplied asexually by cutting and re-attaching branch sections.
Fragging / Asexual Propagation
To frag a knobby sea rod, cut a branch section with scissors or cutters; cutting a section off a healthy colony does no harm to the rest of it. Secure the cutting to a plug or rock, as most gorgonians encrust onto plugs quickly. Dry the base of the cutting and the plug, apply a couple of dabs of cyanoacrylate glue, and stand the piece upright, since gorgonians are best placed freestanding and secured to rock.
Conditions for Propagation
Good water flow is one of the most important factors in keeping gorgonians, because strong current strips away the shed mucus membrane and keeps polyps extended; photosynthetic species also want moderate to high lighting for several hours a day. With its rapid growth, a well-placed Eunicea cutting encrusts and recovers quickly under brisk flow and good light.
Common Challenges
Weak flow lets the periodic mucus coat linger and algae settle on a fresh cutting, so maintain strong, turbulent current and baste the cutting to clear mucus. Once the base attaches and the polyps re-extend, the colony's rapid growth resumes.