Predators Pests Commensals And Good Guys

Aquarists often wonder whether a new creature they observe is a beneficial organism or a potential trouble maker. In this chapter we want to provide a broad overview of some of the creatures that make reef keeping difficult, some that make it easy, and some that just make reef keeping interesting.


Reef aquarists know that certain types of polychaete worms can wreak havoc on other invertebrates. We discuss two particularly nasty worms here, and refer the reader to volume one for additional information about them.

The "Fire Worm" or "Bristle Worm," Her mod ice carunculata is a voracious predator of gorgonians and anemones. They can also feed on other soft and stony corals. Search the aquarium with a flashlight late at night to spot them during their midnight eating binges, when they are easiest to catch. Don't touch this worm with bare hands! They bear an armor of fiberglass-like bristles that not only imbed in and irritate the skin but also convey a searing pain-inflicting poison.

Another bad worm is Oenone fuIgida, a long orange guy that is active mostly at night feeding on mollusks. It eats snails by first covering them with a mucus blob that suffocates them. The worm then pops off the snail's operculum and eats the meat. As we described in volume one, this worm also bores holes in the shells of tridacnid clams, feeding on their tissues while they are still alive, and often killing them as a result.


While some nudibranchs do not survive in aquaria because of their specialized diets, other species can become pests because they eat corals and multiply in the aquarium.

Phyllodesmium longicirra A. Storace

Nudibranchs m-

Oenone Fulgida Worm

The polychaete Hermodice carun-culataeating a gorgonian in an aquarium. The photograph was taken at night. Immediately afterwards Julian netted the worm. J. Sprung

This Epicystis crucifer bears the evidence of a recent encounter with Hermodice carunculata. Note the worm's shed bristles on its surface. The worm can consume an entire anemone overnight! The aquarist saved this anemone when he saw it being attacked. J. Sprung

Reef Pest SnailsOenone Fulgida Worm

The polychaete Oenone fulgida was first mentioned in Volume One. There we described how it can suffocate a snail by exuding a mucus blob over it. It also bores holes into clam shells and can be devastating to tridacnid clams. This photo shows the worm preparing to eat a snail it has suffocated with mucus. J. Sprung

Oenone Fulgida Worm
The COMPLETE guide to Aquariums

The COMPLETE guide to Aquariums

The word aquarium originates from the ancient Latin language, aqua meaning water and the suffix rium meaning place or building. Aquariums are beautiful and look good anywhere! Home aquariums are becoming more and more popular, it is a hobby that many people are flocking too and fish shops are on the rise. Fish are generally easy to keep although do they need quite a bit of attention. Puppies and kittens were the typical pet but now fish are becoming more and more frequent in house holds. In recent years fish shops have noticed a great increase in the rise of people wanting to purchase aquariums and fish, the boom has been great for local shops as the fish industry hasnt been such a great industry before now.

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