Somehow, after over five years of having SPS-dominant aquariums, I finally got my first case of red bugs. A local aquarist was tearing down his system and gave me a few corals that weren’t doing well. Turns out, they were infested with red bugs AND Acropora-eating flatworms (AEFW). Fortunately, I caught the red bugs while the Acropora was still in my quarantine tank.
Red bugs (Tegastes acroporanus) are extremely tiny copepods (as seen in the red circle below) that solely infest Acropora corals (not Montipora, Pocillopora, etc). They come into the hobby on wild or maricultured colonies (corals purposefully grown and harvested in controlled ocean environments.) They are further spread through aquacultured colonies in hobbyist selling/trading.
A good indicator of a red bug infection is a loss of Acropora tip coloration and browning that cannot be attributed to other factors. The coral below lost nearly all coloration due to red bugs, and the white patches were due to AEFW.
In the early 2000’s, there was a general consensus in the reefkeeping hobby that red bugs only affected smooth-skinned Acroporas and did not bother corals like Millepora, “the green slimer”, etc. due to the extra mucus they produce. Although red bugs do tend to prefer certain Acropora (especially Acropora valida, the “tricolor”), they have been found on most every species. There was also a belief that red bugs laid eggs and had a larval stage, which led to a consensus that three treatments were needed in order to eliminate the red bugs entirely. Although red bugs were eventually determined to be live bearers, I still recommend three treatments just as a safety precaution.
How to Identify:
On corals that have “browned out” due to red bug presence, the red bugs are rather distinguishable. They are mostly yellow (almost a gold color) with a bright red dot and are extremely tiny (think a little bigger than the size of the period at the end of this sentence). Unfortunately they are not easy to see on healthy corals, and they have an ability to hide within the coral polyp itself without being consumed. In order to determine the presence of red bugs, I use a magnifying glass to look for them before placement into my quarantine system, then I observe the coral daily for a week. I also take a photo of each coral and zoom in to look for anything I’ve missed.
How to Treat:
Unlike other serious pests (e.g. AEFW and Montipora-eating Nudibranchs), there is a suitable in-tank treatment for red bugs (see below).
Method 1: Control
Some hobbyists believe that blowing the corals off with a powerhead a few times for a couple weeks will rid the Acropora of red bugs since they may starve before finding their way back to the coral. Other hobbyists rely on natural predation (such as pipe fish, file fish, gobies, wrasses, etc.), but to my knowledge, there are no 100% predators. I advise against natural control methods for aquarists who plan to sell/trade their corals.
Method 2: Coral Dips (Coral Rx, Iodine, TMPCC, Revive, etc.)
Coral dips, such as the ones listed above, often help stun the pests so they can be blown off gently with a pipette or powerhead. Since red bugs are live bearers, this method can work as long as all the red bugs are removed. Since a succession of coral dips work for AEFW and red bugs, I dip all Acroporas daily the first week, every other day the second week, every third day the third week, and then once a week for weeks four through six. I have not lost a single coral with this method, and it saves me the hassle of treating with different medications at different times. I should note that I’ve never found a pest after week two, but I still go the full six weeks since the lifecycle of AEFW is quite long. Also, Coral Rx can be extremely damaging to smooth-skinned corals, so please use caution (or better yet, another dip for them.)
Treatment protocol: Follow dip manufacturer instructions.
Method 3: Interceptor
Interceptor, a prescription canine flea medication, is commonly known as the red bug “cure-all” since it is an in-tank treatment. However, it will likely kill all crustaceans and some microfauna, so make sure to remove all shrimp, crabs, etc. before dosing. Most pods will recover with time, but there will be significant die-off. This die-off can also spike ammonia levels, so be prepared for a water change and to run carbon.
Many people have had difficulty obtaining Interceptor from their vets since treating for red bugs is an off-label use. However, information has been published on the Veterinary Information Network (VIN) about its use. Providing proof of infection to a vet and asking him/her to look up red bugs on the VIN should be enough to receive the medication (or at least it was for us.) Some vets have recommended different medications with different treatment protocol, so those individual cases are not discussed here.
One last note about Interceptor is that many aquarists are finding some red bugs have a resistance to it. If you try Interceptor with no luck, work with your vet to find an alternate medication or try one of the other methods listed here.
Treatment protocol: Dustin Dorton of ORA determined 0.025 grams of Interceptor are needed per 10 gallons of water (thread here). To summarize, an Interceptor pill must be pulverized and weighed out as accurately as possible. All crabs, shrimp, etc. must be removed from the aquarium before dosing. Estimate the true volume of water as close as possible (subtracting live rock, sand, etc.) Turn down the skimmer so that water runs through it, but the skimmer doesn’t actually skim. Remove GFO and activated carbon. Otherwise, allow everything else to run so that the chemical can spread throughout the aquarium. Dose the correct amount and let the system run for six hours. After six hours, the red bugs should be gone, but if they are not, slightly adjust the doseage and try again in a few days. Perform a water change (~15-25%), turn the skimmer back up, and bring the GFO and carbon back online. As mentioned above, although red bugs are live bearers, three treatments a few days apart is still ideal. Once the red bugs are completely eradicated, the crabs, shrimp, etc. may be reintroduced to the aquarium.
Method 4: Bayer Advanced Complete Insect Killer
Yes, this is the stuff you may have in your garage, or if not, you can find it at your local hardware store. This treatment was suggested by Whisperer on ReefCentral (thread), and it is meant as a dip only, not as an in-tank treatment.
Treatment Protocol: Dose 0.5 ml Bayer Advanced Complete Insect Killer per two cups of tank water. Place the coral in the dip for 10 minutes, baste the coral lightly with a pipette to remove the bugs, then gently swish the coral in untreated tank water to remove any remaining chemicals/pests. Place the coral back in the tank and monitor.
Method 5: Lower the Temperature
With the crazy heat this summer, lowering the temperature may not be feasible, but for tanks located in basements during the winter, this may be the least expensive option. In fact, this method worked for me…accidentally! Right after I received the infested Acropora mentioned above, we lost power for about six hours. My quarantine tank got down to about 65 degrees. After the power came back on, there were no signs of red bugs. I’m not the first to document this, and more info can be found in the thread link above. I still continued treating for them just in case, but I never saw another one. This seems to work, but we still need scientific studies to back it up.
Treatment protocol: Slowly lower temperature to 65-66 degrees. If tank inhabitants start to show signs of stress, start bringing the temperature back up. Leave the temperature at 65-66 degrees for 4-6 hours. Note: this is experimental, and there is not enough data to determine if this treatment works 100%. Use with caution!
Thanks to all the courageous mad scientist reefkeepers out there, there are several proven treatments for red bugs, including an in-tank treatment. Hopefully, with the ease of treatment protocol, red bugs will be a thing of the past. Best of luck in your treatment!