bang guy
Moderator
Now that I have your attention I would like to introduce you to the absolute worst animal that could ever make its way into your Reef Aquarium. There are over a hundred different species of Cirolanids and almost half are parasitic.
A closely related group of Isopods called Aegids appear nearly identical but are considered generally harmless. For my personal purposes I group them together since I can't tell them apart. Just keep in mind that there is another large group of Isopods to consider.
As I stated, many of the Cirolanids are harmless detrivore/scavengers but many are bloodsucking parasites. How do we tell them apart? Seeing a small roly-poly bug hanging off a fish is probably the best indication that you're in trouble. The parasitic type normally hides in the sand or a hole in the rock waiting for nightfall and a victim to swim by. They swim blindingly fast and have no trouble overtaking a fish and latching on with the two front claws. Once attached they will quickly start sucking blood or simply eating the flesh. They will eventually kill the fish.
These bugs range in size from 1mm to reports of 3 feet!! There have been a few reports of them attacking and injuring divers and MANY reports of aquarists being bitten. One specific type will attack sharks by burrowing into the body and swimming to the heart where they feast for a few weeks until the shark dies.
The reason I raise the panic bar for these critters is that there's really no cure. They reproduce rapidly in a reef tank with so many places to hide and nothing reef safe to eat them. Their physical speed makes them very difficult to catch. A few types can only live on fish blood and a tank deviod of fish will kill them off after 4 - 6 months. However, many can survive as scavengers between fish meals.
Please share your experiences and any antidotes you may have discovered.
