Acropora Red Bugs (Tegastes acroporanus).

Red bugs are far less concerning than AEFW but, they’re still a concern that need to be addressed.

Red bugs are a tiny crustacean that aggravate acropora corals. It is unlikely that you will see red bugs with the naked eye, the best way to discover them is to use a good DSLR camera with a macro lense, or examine the coral under a microscope.

The problem with red bugs is, if you’ve got these, there’s a very good chance you’ve got AEFW too.

There’s two ways two deal with this pest, biological control or chemical eradication.

Chemical eradication methods.

There is a treatment which can be used in the reef tank, the most popular choice is a drug under the brand name interceptor, which contains milbemycin oxime.

The drug milbemycin oxime is highly toxic to all crustacean life, luckily red bugs appear to be particularly sensitive to it.   I have personally used interceptor before to treat my entire tank for red bugs, I had to import it from the USA under a prescription which was obtained through my local vet, and here it is:




If you want to obtain interceptor, be prepared for a big song and dance and, get ready to educate your vet, as it’s highly unlikely any one will have presented them with a sick acropora before!

The song and dance

First visit to the vet:  I had to visit my vet, explain the problem and the treatment, then I had to give my vet various internet links to websites that detailed this pest.

Second visit to the vet:  I had to bring a branch of the infected coral to my vet for inspection under a microscope, only then would he write a prescription.

Third hurdle: I had to find a US firm that was willing to ship prescription medication to the UK.  As you can see from the above photo, I obtained this through a US firm called

The goodies:  Collection of medication from vets!

The bill:  After doing most of the work and enhancing my vet’s education, I then had to pay him (as expected).

One large interceptor tablet should treat about 1500 litres of water, the tablet must be finely crushed and mixed in a cup of tank water before administering to the tank.  In total, three treatments are needed, each treatment should be about a week apart.

Before you even consider adding this medication to your tank, read this thread first and educate yourself.  Please read various relevant threads on reef central too, knowledge is power.

Caveat:  What ever you add to your tank, is your responsibility and your risk!

Biological control

Biological control will likely keep the red bugs at very low, possibly undetectable levels, but it should not be viewed as a method for eradication.

One of the best animals to consume red bugs is the dragon faced pipe fish,  (Corythoichthys sp.).


Red Bugs

Red Bugs



The above images are taken from my tank, I’ve still got one of these animals today and they make an interesting addition to a marine tank although I would not recommend housing them with anemones.

The below images are of various acroporas with red bugs:

The below shows a single Red Bug & is 
courtesy of Allmost from Reefcentral


The following two photos are from Tony B's tank
red bug
red bug

A caveat to anyone who is considering using interceptor:

A very high proportion of reefkeepers have a sudden onset of AEFW soon after treating and eradicating red bugs.  In my opinion there is a relationship that exists between crustaceans and AEFW.  I think it is incorrect to assume that red bugs control AEFW, as there’s plenty of healthy tanks out there with no AEFW and no red bugs.  My personal view is that we are yet to understand this relationship, I feel the predators of AEFW may be a variety of very small undocumented crustaceans, a lot smaller than red bugs, which are yet to receive classification.  After using interceptor, the reef aquarium is virtually if not totally devoid of crustacean life, which allows AEFW to have a huge upsurge in numbers, with no predators to keep poppulation numbers in check.  This is of course purely conjecture, I have no credible studies or proof.  However after treating with interceptor I got AEFW for the 2nd time in my reefkeeping career.

Another well known and accomplished UK reefkeeper also had red bugs around the same time as me, this guy is Tony Rogers who writes under the username Reefbloke on Ultimatereef.  He too treated his tank with milbemycin oxime and he too experienced AEFW very soon after eradicating red bugs.

If I had red bugs again, I would be inclined to use biological methods of control first, leaving interceptor as the last option.

Further reading on black and red bugs can be found on this link.