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Hitchin' a Ride - Unwanted Inhabitants

Live rock makes a great addition to any aquarium, enhancing the aesthetic appeal with a natural look, while offering benefits to certain organisms. They often house a variety of life forms, ranging from microscopic plants and animals to larger algae and invertebrates including sponges, feather duster worms, microcrustaceans and a long list of others.

Under the proper conditions, the organisms thrive and contribute to the overall health of the entire system by performing specific tasks and functions. Coralline algae and macro-algae are very useful in controlling the growth of nutrient depleting, unsightly algae. Sponges and feather dusters filter out organic materials, keeping the aquarium cleaner and clearer.

Live rock and the aforementioned company create a symbiotic relationship within the aquarium. However, there are a number of organisms that may also crash the party. Three types of these potentially problematic inhabitants are listed below.

Bristle Worms

Bristle worms are oftentimes beneficial to the tank; they keep the tank clean by feeding on detritus and dead organisms. However, an abundant food supply can result in a fast growing population, which may lead to potential attacks on crustaceans, corals, and anemones. They can become unpleasant in appearance as they grow in size. Improved water flow, aggressive skimming, and nutrient control keep their population in check by minimizing their food supply.


Aiptasia acts as an aquarium weed; in certain conditions, a single animal can produce more than 60 offspring per day. Not only do they thrive on excess food, they can reproduce where other, more beneficial species cannot. Once established, ridding your tank of these pests can be difficult. The Copper-banded Butterfly fish is the least-taxing method for long-term control. The flip side to housing this Butterfly fish is they also feed on other invertebrates, such as feather duster worms. Peppermint shrimp are also used to keep aiptasia anemone populations under control.

Mantis Shrimp

If small fish begin disappearing from your tank, the mantis shrimp is a likely culprit. They are also known to eat mollusks and other invertebrates. This problem should be taken care of as soon as possible.

Though difficult to do, the best way to rid these predators is to trap them, either by using a fish trap or by waiting until they crawl into a rock and then removing the rock. To prevent these problems, properly cure your live rock before adding it to the aquarium. During the curing process, examine your live rock carefully and remove unwanted organisms; once properly cured, the key to a thriving live rock habitat is to maintain proper water conditions. It is also important to not allow water conditions to deteriorate. Nutrient-rich water will cause these problem organisms to grow rapidly. The diversity of live rock and its beneficial inhabitants not only provides aesthetic benefits but, more importantly, contributes to the overall health and success of your marine aquarium.

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