Tegastes acroporanus, also known as the Red Acro Bug for the red coloration on its body and its prey, Acropora, are copepods in the family Tegastidae. They are parasitic on the hard coral reef building corals in the genus Acropora, and feed on these corals exclusively. Though it has been found on all types of Acropora, it seems to be less predominant on species with large, “hairy” polyps such as the species A. millepora. Being a copepod, they are very small, and many times can be hard to see with the naked eye. However, their existence on a suspected affected Acropora can be determined either by looking for the typical symptoms of T. acroporanus or by shining a flashlight on the suspected Acropora and looking for tiny fluorescent specks, caused by the light bouncing off the red pigment in their bodies.
When on an Acropora they remain, for the most part, stationary and will spend most of their time consuming the tissue of the acropora. They are very difficult to dislodge once stationary, using their appendages to latch onto the Acropora and are not removable even by suction or strong water movement, which may in turn, damage the Acropora. A small number will leave a coral if the coral is disturbed and will swim in the water column, looking for another host.
First reports of this aquatic pest came in the early 2000s and the infestation sped quickly throughout the marine keeping hobby around the world with the popularity of coral fragment trading. Due to the potential threat of this parasitic copepod to the hobby, many different treatments have been tried and testing through the years and it is now possible to stop or at least slow the infestation of T. acroporanus
Symptoms
While Tegastes acroporanus or the red acro bug is a parasite on Acropora corals, it does not always kill them. The overall health of the host prior to infestation, the overall health of the aquarium system, and the degree of colonization will contribute to whether or not an affected Acropora can withstand the infestation
There are several possible signs of an infestation of red acro bugs:
reduced extension of polyps and/or the coral tissue
change in coloration, typically involving a loss of colored pigments from tips and branches, and a change to a more uniform brown color
reduced or stalled growth rates
loss of tissue pigmentation including the loss of zooxanthellae pigmentation resulting in a bleached appearance
local or colony-wide tissue loss, possibly as a result of colonization stress rather than from direct consumption of tissue by predation
death of the colony
Treatments
The Dorton Treatment (dosing Interceptor)
Warning: Use this medication at your own risk. While most recorded usages of this treatment have yielded a positive effect, there is always a risk with usage. The medication Interceptor was not designed for usage in marine aquariums.
In 2004, a “cure” to red acro bugs was posted on the forum Reefs.org by the user DustinDorton. It involves the usage of a dog heartworm medication called Interceptor, made by Novartis. Interceptor is the industry name for milbemycin oxime, which is an active chemical against nematodes (or heartworms in dogs) and some arthropods, such as the red acro bug.
The dosage used in an aquarium to kill red bugs is 25 mg per 10 gallons of actual tank water. That is 25 mg of the entire tablet. Each tablet in the pack of 6 will treat about 380 gallons. The tablets are ground with a mortar and pestle into a fine powder.
The entire volume of water in the system must be considered as the pill will dissolve into the whole system, not just main aquarium. Thus, it is necessary to take into account things like the sump, a refugium, the water in a skimmer, calcium reactor, canister filter, or any large pieces of plumbing. Also, before adding the medication to your tank, turn off your skimmer and any UV sterilizers and ozone generators. Then, remove any mechanical filtration and carbon if present.
Remove any shrimp or crabs that you want to save. They will have to stay out of the system for the duration of the treatment. However, be warned that if you add them back to your tank, there is a slight chance that you will re-introduce the red bugs to your tank.
The next step is to dissolve the medication into some aquarium water, a process that will likely require stirring, as the powder is not very water soluble. Then, spread the mixed water evenly across the surface of the water. Your tank should remain perfectly clear and look normal the entire time. The bugs hang on well into the 4th and 5th hour of the treatment as their appendages will still be hanging onto the flesh. Many of the bugs may even hang on for days even after they are dead.
If anything goes wrong during treatment perform a water change ASAP and add a large amount of carbon to your system.
After 6 hours, a 25% minimum water change is performed and as much activated carbon as you can fit should be added to the tank. In the initial tests, crustaceans that were reintroduced to a tank after a 25% water change and carbon were unaffected by the medication. 24 hours later the water should be changed again and the carbon replaced. There is no maximum for the water changes or carbon, the more you do the better.
The treatment needs to be performed a minimum of 3 times as the medication does not kill them at every stage of their life. Thus, even though most adults may be killed in the first treatment, there may be some juveniles and eggs that remain which were not affected by the treatment. The third treatment is a “just in case” treatment, its goal is to get any bugs that could have possibly survived the first two.
The most likely side effect of this medication is that it will likely kill off most of the crustaceans in your aquarium, including all crabs, shrimps, mysis shrimp, and copepods. As mentioned, if you want to save any of your crustaceans you have to remove them before treatment. Also, if you have any fish or other animal that relies almost exclusively on micro-crustaceans for food, it may be better to evacuate them to another tank as this treatment will likely wipe out most of your micro-crustacean population.
Natural predators
Research indicates the dragonface pipefish Corythoichthys haematopterus is a natural predator of the red acro bug.
Copyright: Wikipedia information about Red acro bugs – This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Red acro bugs". More from Wikipedia