Ocean’s (Day) 2012

Today is official World Ocean’s Day. In honor of the occasion, I thought I’d talk a little about something that lives in the sea.

Aquatic Worms.

The worm above is a “hard-tube” feather duster, of the family polychaeta. The family includes a wide variety of worms, not all of which are sedentary or tube-dwelling varieties. In fact, the bristle worms which hide in live rock and feed on detritus are also polychaetes.

Whether you know them as “fan worms,” “peacock worms,” or “feather dusters,” the tube-dwelling polychaetes are popular with reefkeepers for their bright colors and feathery feeding cones.

The cone-shaped protrusions are attached to the worm’s head and can be shed and regrown. Worms “blow their cones” in response to predators, stress, or poor water conditions. Some also shed the cones and grow new ones periodically as part of the growth process.

Many novice aquarium keepers find decorative worms difficult to keep because of their sensitivity to water quality – salinity, temperature, nitrate levels and the availability of live phytoplankton are critical to these lovely invertebrates’ health and long-terms survival. They are filter feeders and need a regular diet of microscopic plankton and dissolved foods to keep them healthy.

Feather duster worms do well in seahorse tanks for several reasons.

First, seahorses are messy eaters. They blow macerated food “clouds” out of their gills, exhaling tiny particles of food which the worms can eat. In addition, seahorses require gentle tankmates – the kind of fish and invertebrates that also tend to leave peacock worms alone. Finally, seahorses require very clean, balanced water parameters – the very same ones the worms favor.

In turn, the hard-tube worms provide “hitching posts” for seahorses to sit on (and occasionally soft hitches too – my worms have all learned to tolerate seahorses hitching to their feeding cones).

Many people think it sounds odd, at first, to keep a worm as a pet – but few think so after watching them in action. If you keep a reef tank and want an interesting invertebrate addition, I’d definitely recommend giving one of these worms a try.