Invertebrate Pests

Some invertebrates become serious pests and should be avoided where possible. Pyramid snails, which prey on giant clams, provide a good example. They can be controlled by adding a neon wrasse to the tank. Other types of pests offer more of a challenge.

Understanding Invertebrates 75

Understanding Invertebrates 75

Harbor Anemones

Aiptasia, variously known as harbor or glass anemones, can live in warm water with a heavy load of nitrate, phosphate, and organics, in fact thriving under such conditions. Yellow brown and from tiny to a few inches in height, they can multiply to plague proportions. Able to sting tank mates with deleterious results, they can be controlled by adding a copperband butterflyfish, Chelmon rostratus, or anemone-eating shrimps, such as Rhynchocinetes. Neither predator is entirely satisfactory because they may not limit themselves to Aiptasia. Corals and other polyps may be in jeopardy. If a fish or shrimp placed in the aquarium for anemone control starts feeding on desirable specimens, the aquarist is faced with the problem of removing the offender to a new home. The anemones can regenerate easily from even a tiny piece left behind, and the problem soon returns.

Taking care not to introduce Aiptasia in the first place is the best solution, but this is more of a challenge than it sounds. Any individuals that go unnoticed will be producing offspring in a few months' time. Maintaining the correct conditions and keeping nutrient levels low in your minireef works against the interests of the Aiptasia, and may help to limit their multiplication. If you can find it, there is a nudibranch, Dondice occiden-talis, that eats Aiptasia and nothing else, but no surefire solution exists.

Mantis Shrimps

Mantis shrimps can be troublesome. Living as they do in burrows or crevices within live rock, they can arrive in the aquarium uninvited and proceed to dine on fish or other invertebrates. They can be tricky to catch. It may be necessary to remove the entire rock containing the shrimps to a bucket of seawater, which will give you a better opportunity to extract them. The presence of a single small mantis shrimp in the tank is hardly cause for panic. Drastic measures should be taken only if you determine for certain that the mantis shrimp has actually done some damage. Mantis shrimps are active mostly at night, and this is a good time to observe the tank for their presence. The particular species you may have is not important. They all look basically similar, like a small shrimp or lobster, with large stalked eyes that can be rotated in all directions to search for food or recognize danger. The characteristic forelegs look like the raptorial appendages of a praying mantis (hence the name "mantis shrimp"). A mantis shrimp may lash out with these and cause a nasty cut, so do not attempt to handle it barehanded. One large species found in temperate seas is called thumb splitter by fishermen, who use them for bait.

0 0

Post a comment