Red Bug Parasites (Tegastes acroporanus)

Red Bugs Circled on Acropora Coral

Somehow back in the day, after over five years of having SPS-dominant aquariums, I got my first case of red bug parasites. A local aquarist was tearing down his system and gave me a few corals that weren’t doing well. Turns out, red bugs AND Acropora-eating flatworms (AEFW) infested the corals. Fortunately, I caught the red bugs while the Acropora was still in my quarantine tank.

Red Bugs Circled on Acropora Coral

Red bug parasites (Tegastes acroporanus) are extremely tiny copepods (as seen in the red circle in the photo) 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), and hobbyist selling/trading of aquacultured corals further spreads them.

Acropora Coral with Parasites

A good indicator of a red bug infection is a loss of Acropora tip coloration and browning that cannot be attributed to other factors. Red bugs caused the coral shown to lose nearly all coloration, while AEFW caused the white patches.

In the early 2000’s (now I’m dating myself), there was a general consensus in the reefkeeping hobby that red bugs only affected smooth-skinned Acroporas. Hobbyists assumed they did not bother corals like Milleporas or “the green slimer” due to the extra mucus they produce. Although red bugs do tend to prefer certain Acropora (especially Acropora valida, the “tricolor”), most every Acropora species is susceptible. Hobbyists also commonly believed that red bugs laid eggs and had a larval stage. This led to a consensus that three treatments were needed in order to eliminate the red bugs entirely. Although research eventually determined that red bugs are live bearers, I still recommend three treatments just as a safety precaution.

How to Identify:

On Acropora 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. They are also extremely tiny at around 0.5mm (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. After that, 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 Red Bug Parasites:

Unlike other serious pests (e.g., Montipora-eating Nudibranchs), there is a suitable in-tank treatment for red bug parasites.

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 (e.g., pipe fish, file fish, gobies, wrasses), but to my knowledge, no predators have a 100% success rate. I advise against natural control methods for aquarists who plan to sell/trade their corals.

Method 2: Coral Dips

Coral dips often help stun the pests so they can be blown off gently with a pipette or powerhead. Since red bug parasites 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. After that, I dip 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 for different parasites 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 (and I always treat for both AEFW and redbugs). Also, some dips can be extremely damaging to smooth-skinned corals, so please use caution if you plan to treat one of these.

Coral Dip Treatment Protocol for Red Bug Parasites:

Follow dip manufacturer instructions.

Method 3: Prescription Flea Medications

Before the manufacturer discontinued it, hobbyists considered Interceptor (milbemycin oxime), a prescription canine flea medication, as the golden standard for red bug parasite treatment. However, as it killed all shrimp, crabs, and other crustaceans, aquarists had to remove them before dosing (the pod population recovered with time). This die-off would also spike ammonia levels, so reefkeepers had to be prepared for a water change and to run carbon. Many people had difficulty obtaining Interceptor from their veterinarians since treating for red bugs is an off-label use. However, the Veterinary Information Network (VIN) published information on red bug parasites for reference.

Once Interceptor was no longer available, reefkeepers began searching for a replacement. Currently, Milbemax is the most often recommended replacement. It is a prescription combination of milbemycin and praziquantel. (The latter medication is commonly used for fluke treatment in reef tanks (e.g., PraziPro); however, it is a much lower dose than would be effective for common marine flukes).

Providing proof of infection to a veterinarian 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 veterinarians have recommended different medications with different treatment protocol (e.g., MilbeMite Otic), so those individual cases are not discussed here. Unfortunately, many aquarists are finding some red bugs have a resistance to milbemycin. If you try it with no success, work with your veterinarian to find an alternate medication or try one of the other methods listed here.

Interceptor Treatment General Protocol for Red Bug Parasites:

(This is provided for historical purposes only since Interceptor is no longer available, as it may be relevant to other treatments.) Dustin Dorton of ORA determined 0.025 grams of Interceptor are needed per 10 gallons of water. After that, the protocol is the same as Milbemax, described below.

Milbemax Treatment General Protocol for Red Bug Parasites:

(Obtain actual procedures from a veterinarian, as this is for general reference only.) The recommended dosage is 23mg per 400g tank water, which works out to 0.0575mg per gallon tank water (or 5.75mg per 100 gallons if that is an easier reference point). Similar to Interceptor medication, pulverize and weigh the medication out as accurately as possible. Estimate the true volume of water as close as possible (subtracting live rock, sand, etc.)

Remove all crabs, shrimp, and other crustaceans from the aquarium before dosing. Turn down the skimmer so that water runs through it, but the skimmer doesn’t actually skim. Remove GFO and activated carbon. Add an airstone (or multiple, depending on the size of the tank) bubbling gently to help maintain the pH. 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 dosage 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 and the medication is removed, reintroduce the crabs, shrimp, and other crustaceans to the aquarium.

Method 4: Bayer Advanced Insecticide

WARNING: Per Bayer Advanced Insecticide’s labeling, “It is a violation of Federal law to use this product in a manner inconsistent with its labeling.”

Yes, this is the stuff you may have in your garage or at your local hardware store. Some aquarists use it as a dip only, not as an in-tank treatment. This website does not cover Bayer use as a coral dip, due to the warning above.

Bayer Advanced Insecticide
Bayer Advanced Insecticide

Method 5: Temperature Adjustment

With crazy heat in the summers, lowering the tank 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 (thanks to being in Utah in the middle of winter). After the power came back on, there were no signs of red bugs. I’m not the first to document this. 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.

Experimental Temperature Treatment Protocol for Red Bug Parasites:

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% or is safe. Use with caution!

Conclusion:

Acropora Rehabilitation Before and After

Thanks to all the courageous mad scientist reefkeepers out there, there are several proven treatments for red bugs, including an in-tank treatment. The Acropora shown was saved from both red bugs and AEFW! Hopefully, with the increasing ease of treatment protocols, red bugs will be a thing of the past. Best of luck in your treatment!

Dying Lithophyllon Coral Rehabilitation

Dying Lithophyllon Coral Rehabilitated
Dying Lithophyllon Coral

A local fish store (LFS) called me to ask if I wanted to try to save some of their corals. An employee had overdosed their reef tanks with a chemical used to treat flatworms (I was not told what chemical it was). When I arrived, honestly, I was shocked at how bad many of the corals were. I don’t know if these corals were dying from an overdose of some unknown chemical or if the flatworm toxins were killing them. Either way, something was poisoning these corals to death. I picked up two “chalice” corals, amongst others. These dying Lithophyllon coral mouths were gaping open, the tissue was falling off, and what tissue did remain was barely hanging on. Rehabilitation was going to be dicey. (Photo of Litho#1 taken 11 May 2013)

Dying Lithophyllon Coral Inspection and Dipping:

Dying Lithophyllon Coral

When I brought them home, I temperature acclimated them to my quarantine tank and prepared the dips. Like most of my rescues, I dipped the corals for pests. (Photo of Litho#2 taken 11 May 2013)

*NOTE: This post tracks the corals as “Litho#1” and “Litho#2” to show individual progress.

Coral Quarantine:

Lithophyllon Coral in Quarantine

After the dips, I placed the two dying Lithophyllon corals into my quarantine tank in a low light, low flow area. I made sure that no crabs would bother the coral, especially with all the decaying tissue. Since the corals were poisoned, I made sure the quarantine tank had new carbon to help absorb anything that the corals might leach. Both corals did start to quickly recede, so I tried to stop it by smearing a bead of superglue gel along the receding edge (white lumpy band in the photos below). Rehabilitation was definitely already proving rough. (Photo of Litho#1 taken 11 May 2013)

Receding Lithophyllon Coral
Receding Lithophyllon Coral (Photo of Litho#1 taken 9 June 2013)
Receding Lithophyllon Coral

The corals also refused to eat until about a month after I received them. I started them on fish food pellets (shown here and above) since they are quite processed. In my experience, sick corals seem to digest fish pellets better than whole foods (like mysis, etc.) This helps them recover faster. (Photo of Litho#2 taken 9 June 2013)

Coral Grow-Out:

Recovering Lithophyllon Coral

After stopping the recession with superglue and maintaining regular feedings, the corals started to heal quickly. And how great they started looking! After 30 days in quarantine, I inspected, re-dipped, and placed them into the grow-out tank. (Photo of Litho#2 taken 4 August 2013).

Rehabilitated Lithophyllon Coral

Regular feedings likely helped the coral recover. (Photo of Litho#1 taken 12 October 2013)

Rehabilitated Lithophyllon Coral

Here is Litho#2 on 3 November 2013.

Rehabilitated Lithophyllon Coral

A month later (8 December 2013), Litho#2 was growing down its skeleton.

Fully Rehabilitated Lithophyllon Coral:

Rehabilitated Lithophyllon Coral

Nearly a year later, both previously dying Lithophyllon corals were growing rapidly. This Litho#2 is shown on 1 May 2014, when it was fully rehabilitated. Below is a close-up shot showing the corals’ beautiful patterns.

Lithophyllon Coral
Lithophyllon Coral Close-up

Conclusion:

I had very little hope for these dying Lithophyllon corals due to their poisoned state. However, the fast reaction of the LFS along with continued care over a year fully rehabilitated these two corals. Shown below are the before/after photos of the dying Lithophyllon coral rehabilitation. One coral was nearly immediately rehomed, and the other coral was rehomed a couple years later.

Dying Lithophyllon CoralRehabilitated Lithophyllon Coral
Before and After: Dying Lithophyllon Coral Rehabilitation (Litho#2 shown)

Dying Cyphastrea Coral Rehabilitation

Dying Cyphastrea Coral Rehabilitation
Dying Cyphastrea Coral

Cyphastrea coral are usually very hardy and prefer low light (and sometimes do best partially shaded) but can be acclimated to higher-light areas. They also adapt well to a variety of flow conditions. I received this dying Cyphastrea coral from a reefkeeper who was getting out of the hobby. Good husband would likely be key to this coral’s rehabilitation. (Photo taken 22 May 2012)

Unfortunately, most corals in the tank were suffering from poor water quality, and this Cyphastrea was no exception. The reefkeeper did the responsible thing by recognizing that the corals needed proper care and attention.

Note how some of the polyps still have tissue while there is no tissue between the polyps. This is a good indication of poor water quality (in addition to actually speaking with the previous owner). Regardless of the damage root cause, I still dipped and checked it for pests.

Coral Quarantine:

Dying Cyphastrea Coral in Quarantine

As mentioned, the coral was declining due to poor water quality. After the initial dipping process, I placed the coral into my quarantine tank for observation and acclimation. Here, the coral was fairly low in the tank to allow it to adjust to the lighting. Notice that by less than a month later (15 June 2012), the coral was already regrowing!

Dying Cyphastrea Coral in Quarantine

Just another 15 days later (30 June 2012) and slightly over a month total time with me, and the coral was gaining coloration and growing rapidly! Given the proper light and water conditions, this coral grows extremely
fast.

Fully Rehabilitated Coral:

Cyphastrea Coral Rehabilitated

This previously dying Cyphastrea coral was completely rehabilitated in less than three months (pictured at 14 August 2012). The coral had completely covered the old skeleton and had encrusted onto the base. In fact, it started to grow so quickly, that I had to frag it several times. Coral reproduction via fragmentation reduces hobbyist impact on the oceans.

Troubleshooting Dying Cyphastrea Corals

As mentioned above, if the Cyphastrea coral has started to lose tissue between the polyps, then there is probably a water quality issue. If the coral is bleaching, then it’s likely in too high of light (or might’ve been in absolutely no light.) If the coloration isn’t great (too brown), then it may need more light or less nutrients. Or, if there’s recession from one side to another, then it may be a pest, bacterial/fungal infection, or a sudden water quality problem.

Dying Cyphastrea CoralCyphastrea Coral Rehabilitated

Plerogyra Rehabilitation

Plerogyra Bubble Coral Rehabilitation

This Plerogyra (“bubble coral”) was significantly damaged on 14 July 2012. The damage was so new that the tissue was still attached.

Although the coral looks worse here (15 August 2012), the damage was stopped.

By 7 October 2012, the coral was mostly recovered and growing again.

Here, the coral is completely recovered and beautiful! (21 October 2012)

Only three months went by between when this Plerogyra (“bubble coral”) was damaged and fully recovered.

Lobophyllia Rehabilitation

Lobophyllia Rehabilitation

This Lobophyllia coral was badly receded, as shown by the remaining pink skeleton. 14 July 2012

Recovering Lobophyllia

By only a month later, on 14 August 2012, the coral was mostly healed and regrowing.

Recovered Lobophyllia

About six months later, 6 January 2013, the coral was fully healed and growing well.

Thriving Lobophyllia

Although the coral’s growth rate was not ideal, by 11 August 2014, it had formed a second polyp. Coloration was also phenomenal.

In 2.5 years, this Lobophyllia coral went from nearly dead to thriving with a new polyp.

Dying Homophyllia Bowerbanki Coral

Bowerbanki Rehabilitation

This dying coral (Homophyllia bowerbanki) was found injured at a local fish store on 10 February 2013. A fish had been nipping at it, which made diagnosis easy. This was a low risk rescue for me, and Homophyllia bowerbanki is my favorite species of coral – a win!

By 31 March 2013, the coral was recovering nicely.

The coral recovered after four months (15 June 2013).

As the coral flourished, so did its colors (2 November 2013). Never did I expect a stunner like this!!

Dying Homophyllia Bowerbanki CoralRehabilitated Homophyllia Bowerbanki Coral
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