While far from a disaster, I would not call it a success… yet. Here is my hopefully brief encounter with Acropora Eating Flatworms. Rewind to about 4 months ago, I had seen what looked like bite marks on the underside of an Acropora nana fragment. The bites never noticeably spread and I initally attributed the discoloration to shading [...]
While far from a disaster, I would not call it a success… yet. Here is my hopefully brief encounter with Acropora Eating Flatworms.
Rewind to about 4 months ago, I had seen what looked like bite marks on the underside of an Acropora nana fragment. The bites never noticeably spread and I initally attributed the discoloration to shading and lack of light reaching the tissue. I inspected other corals and found no other signs or evidence showing their presence.
Below is the said fragment just prior to treatment. The fragment tipped over for a few days which is when the bite marks became obvious.
Seeing the increase in bite marks, the first treatment I attempted was basting. Basting knocks off the flatworms, which are then often eaten by fish from the water column. Just one burst of water and the flatworms flew off the coral. In hindsight, I would have timed the basting differently…
I had decided I wanted to treat the tank. All the corals are fully encrusted on rocks, but our minimalist aquascape (3 rocks total) made the process relatively pain free. I used the opportunity to remove our large Montipora capricornis. Now that it is removed, visually the glassbox is much more open. I was also forced to chisel off our large Acropora horrida colony.
For treatment I went with Two Little Fishies Revive. Julian Sprung was nice enough to send us a bunch of the product for our Oktoberfest giveaway and to do some testing myself. There has been some debate on the forums regarding Revive’s effectiveness on AEFW and Red Bugs (Tegastes acroporanus). I wanted to see how effective it was on each pest… but I was not planning on testing it on my own corals!
The AEFW infestation caught me by surprise and a broken camera and crashed computer have left me with little to present in terms of evidence. I can say that Revive is very effective in eliminating Acropora Eating Flatworms from Acroporas. In just a few seconds most of the FW would jump from the coral while l I gained great pleasure from their demise and ultimate death.
Sidenote: No treatment so far (Revive, Fluke Tabs, Tropic Marin Pro Coral Cure, etc.) eliminates eggs. For this reason multiple treatments are needed.
Revive is made from natural extracts of Oleum abietis (Pine Oil) and Citrus limon (Lemon). When added to aquarium water it clouds slightly, and yes it does smell like Pinesol. TLF recommends 40ml per gallon. We used just over 4 gallons of water and 200ml of Revive. Corals were gently swirled in this solution for 4 minutes, with the largest rock getting a 6 minute dip for good measure.
Some FW lasted longer before jumping, but could be convinced otherwise by dunking and swishing the coral or rock. Here is our smallest and most infected rock in mid-dip.
After the treatment, corals were placed immediately back into the display tank. A few minutes after most had their polyps out and looked happy. The largest rock containing our A. nana that received an extra 2 minutes in the dip showed no initial signs of distress until a few days later. Here is the Acropora nana mother colony before treatment.
Here it is just yesterday at a different angle.
Polyp extension is still good, but coloration has dulled significantly. Interestingly no other corals have shown signs of browning out, including a large fragment of the colony that only received a 4 minute dip. Lesson learned? 6 minutes is too long. On a positive note, no AEFW or bite marks have been spotted since the dip.
Three of my favorite “deep water” corals did not respond well to the treatment. A. simplex, A. turaki, and A. rambleri were extremely sensitive to the dip. A. rambleri has recovered and now looks as it did pre-dip, however the Turaki and Simplex are just about lost. The tissue did not slough off like Rapid Tissue Necrosis (RTN) but faded away slowly. Now just a few tips are alive and well, but I fear they may not make it through the week. We will see. After this experience I would advise shorter less potent dips for these “deep water” Acroporas. Unfortunately their soft skin also makes them prone to AEFW attacks.
After the round of treatment this is the waste that was left behind. Flatworms and Amphipods make up most of the waste with algae and detritus mixed in as well.
Earlier I had said that in hindsight I would have changed the timing of the initial basting. Just two days after the basting AEFWs had spread from just one coral to nearly all “soft textured” Acroporas. Perhaps a coincident, but the 4+ months prior to basting the AEFW were kept in check and did not spread. Because they do float around the tank, common sense tells me it would have been smarter to dip first before basting at all. A “Duh” moment on my part, and something that should be considered before taking the basting approach. If you can access an infested coral, there is no reason to risk spreading AEFW to others. Give it a dip and save basting for the inaccessibles.
Over the 4 months that the AEFWs did not spread our Chaetodon declivis grew particularly fond of the infected fragment. Not damaging polyps, but picking at something. The increase in bite marks occurred when this coral tipped on its side which made that area unreachable to the butterfly. I cannot say the Declivis significantly preyed upon the FWs, but after the FWs spread I have observed ours eat them direct from Acroporas. Often spitting the FW back out before taking another attempt to eat it.
This is based on one single experience, but I would not be surprised if Chaetodontids preyed upon AEFWs in the wild.
I can attest, Acropora Eating Flatworms are not fun. But they’re also not the end of the world. Many well known SPS dominated tanks seen across the forums have AEFWs and never treat corals beyond occasional basting and natural predators. Whatever “treatment” method is used, I hope this helps in your own experience. We have two more dips planned, and I hope this will be the last of AEFWs in the glassbox.
For more information on Acropora Eating Flatworms I encourage you to check out the following sites:
