A lot of us are pretty careful to avoid introducing pests when building and adding to a reef aquarium or refugium. This effort indeed pays off tremendously in the long run. As in so many cases, “an ounce of prevention is worth a pound of cure.”
Still, the occasional unwelcome critter will slip through the cracks. Maybe they hitchhiked in on some big live rock shipment you just received (there was just too much rock to closely inspect in the available time!). They may even have gotten in (safely tucked away in a little crevasse) via a small piece of rock that you just bought your last coral on. Doesn’t matter. All that really matters now is how long you wait to act.
Take effective actions now and you might eradicate the pest quickly; leave it alone and it will almost surely proliferate rapidly to become a plague.
The stubborn invader
There are no known water treatments that effectively kill pests without harming desirable aquarium inhabitants. This is certainly so with glass anemones (Aiptasia pallida). Indeed, glass anemones are overall much tougher than the average aquarium animal. They don’t even seem to have some sort of Achilles’ heel. It’s not a bad thing to go after the big ones with a syringe and one of those packaged Aiptasia poisons. However, total eradication requires that effective measures are taken to kill both young and mature individuals.
Fortunately, Aiptasia are apparently slightly more palatable than the average anemone, coral or corallimorpharian. This means that a small handful of reasonably reef-safe creatures can be deployed to eliminate them biologically. In other words, to eat them.
Among the popular means of biological control of Aiptasia at this time include the peppermint shrimp, the Molly Miller blenny and the aiptasia-eating filefish. Each has its own merits. But what about using them together? Is the combined Aiptasia-killing power of the trio greater than that of each individual?
In plague proportions
Glass anemones grow very rapidly under aquarium conditions. More pointedly, they reproduce rapidly under aquarium conditions. They owe their sometimes explosive population gains to pedal laceration. This clonal mode of reproduction (which more or less involves an individual leaving behind a piece of foot that grows into a new individual) makes invasion easy. It’s hard enough to see a mature individual that is closed up in a hole; imagine how difficult it is to spot the miniscule clones, even on a little coral plug!
Now imagine what happens once they start releasing clones all over your aquarium. Since very, very few animals eat them, and they grow so quickly, Aiptasia can in short time multiply to fill all available growing space. Then, they start to elbow outward, using their highly venomous tentacles to kill or chase away their neighbors. Generally, these neighboring animals will be your corals. And clams. And zoanthids. You get it.
Because of their high-speed reproduction and their ability to deposit small clones in hard-to-reach places, by the time you see one glass anemone, you likely have scores of them (or soon will!). The best time to act is right away. The best thing to do is to deploy a small force of specialized Aiptasia killers.
The best choice of creatures for this crack team? That would be three hardy species that have been known in the hobby for some time now and are all available as captive-bred: The peppermint shrimp (Lysmata wurdemanni), the Molly Miller blenny (Scartella cristata) and the aiptasia-eating filefish (Acreichthys tomentosus).
Glass anemones are not safe in a tank that houses all of the above listed species. A tiny anemone or two could possibly escape the clutches of any one of these species. But when confronted with the trio, Aiptasia are doomed. There is simply nowhere for them to hide. Sure, some pale, weak, wussy individuals could subsist deep within the rock structure where their predators cannot reach; but away from the surface (where light and food is abundant), they lose their infamously fierce competitive edge.
Peppermint shrimp have been tried many times for this purpose (certainly in part because of their perfectly reef-safe behavior) and are widely accepted as reliable Aiptasia-eaters. They are sometimes reported to ignore the pests (likely in situations where they are otherwise well-fed). Thankfully, when the true peppermint (L. wurdemanni) is used, glass anemones are generally in big trouble. Most feared is the shrimp’s ability to probe deep into the tiny holes and crevasses where the anemones are accustomed to taking shelter.
Another dreaded predator is the Molly Miller. After some years of skepticism, it seems at this point that this homely little fish does indeed have a particular taste for Aiptasia. It’s possible that they scrape up and eat the minute juveniles while grazing. They reportedly have consumed large (and small) individuals in some cases, though in others they are reported to eat only the smaller ones. It does seem that this fish (like the peppermint shrimp) needs to be sufficiently hungry to target glass anemones; as a matter of fact, overfeeding not only contributes to additional waves of Aiptasia proliferation, but will also discourage your Molly Miller blennies from attacking them! When really hungry, Molly Millers eat detritus, meaning that they not only can be a deadly predator of Aiptasia but also a competitor for a shared food resource.
Finally, we introduce the aiptasia-eating filefish. Given their name, what more could we say? This is what you bring in to eat the big ones. We definitely would call to attention some reports of this fish nibbling on the polyps of both soft and stony corals. If this occurs, it is said to happen shortly after the glass anemones have all been consumed. Considering the small handful of truly negative reports and the thousands of A. tomentosus acquired and used for this very purpose to date, it seems the usual results are positive. Therefore, like many other dealers, we advise their use, but we advise their use with caution.
And did we mention all three species are available as captive bred? Stock oodles of them in both the display tank and the refugium knowing that they were produced sustainably, are guaranteed disease-free and are completely adapted to captive life!