Cavernularia sp.
| Care Level | Expert |
| Lighting | Low (non-photosynthetic) |
| Water Flow | Moderate |
| Placement | Deep sand bed (anchors in substrate) |
| Aggression | Peaceful |
| Coloration | White, cream, pink or purple feather |
Overview
The Sea Pen is an unusual non-photosynthetic octocoral shaped like an old-fashioned quill — a fleshy central stalk lined with feathery polyp-bearing branches. It anchors its bulbous foot in soft sand and expands at night to feed.
Care & Placement
It requires a deep, established sand bed several inches thick to anchor and bury its foot. Non-photosynthetic, so lighting is irrelevant; provide moderate flow. It buries by day and inflates its “pen” at night, and often relocates itself.
Feeding
Non-photosynthetic — it must be fed frequently with live and frozen zooplankton, rotifers, phytoplankton and fine particulate foods, ideally after dark when expanded. Very difficult to feed adequately.
Propagation
Not propagated in the aquarium.
Cautions
EXPERT ONLY — one of the more difficult NPS animals; most specimens slowly starve in typical reef tanks. Needs a deep sand bed and a heavy, targeted feeding regimen.