Quote:
Originally Posted by katydid
...They don't really move while you watch them, but if you poke them a little with a fingernail, they will re-orient and move. Can anyone tell me what they are, and how to get rid of them? They are getting out of control. I've scraped some off when I scrape algae, but they keep coming back. Thank you!
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This will be hard to believe, but plain 'ol water is the dip of choice to kill flatworms. It does help to mutter "DIE SKUM!!!" while dipping and swishing the rock for the 10 to 15 seconds it takes to rupture the flatworms.
FW has such a severe osmotic effect on flatworms coming from full strength seawater that it literally ruptures their bodies as the water rushes into the flatworms to dilute their interstitial space contents. Make sure to discard the FW where it will not have any direct contact with aquatic or marine environments, as the flatworms release a toxin into the water as their bodies lyse that has potential of killing vertebrates and other higher organisms. If you have to dip your corals, I'd limit the dip to a short period (less than 15 or so seconds), however, there are some that suggest 60 second soaks
which, although that might be OK for zoanthids, etc, I'd not do it for
stony corals straight out of SW.
You may want to investigate the use of Flatworms EXIT by Salifert. The product itself is not toxic to fishes when used up to several times the recommended dosages, however, the flatworms that are killed by the product release their toxins into the aquarium's water column, potentially killing many of the fishes and/or clams, etc in your systems. If you're not taking down your system,
Flatworm Exit by Salifert might be a possibility, but make sure to remove as many flatworms as possible via siphoning or rock dips outside the aquarium before treatment, then make sure to use the activated carbon followup as instructed in the packaging for the product. I believe that JennM had a good thread here somewhere on the topic and listed her experiences with an application of the product. Try doing a search on Flatworms and JennM to see what turns up. I have also seen systems clear of Flatworms as a result of reductioin of nutrients and thorough siphoning on a regular basis in conjunctioin with a reductiion of photoperiod for a few days (you might even try lights out for a few days instead of reduction) along with physically removing your rock and dipping it in FW baths. Many experiences on the 'Net for this subject.
http://thereeftank.com/forums/showthread.php?t=105602
http://www.seaslugforum.net/display.cfm?id=5836
Although I would not recommend them for this tank, Leopard wrasses seem to be about the best of the wrasses for cleaning up Acoel flatworms, only problem is they are a difficult species to acquire and keep alive, usually shipping is really tough on these little beauties. A more effective biological cure would be the nudibranch
Chelidonura varians, but they are VERY difficult to keep alive in a reeftank with good current, as they do not keep a good grip on the substrate, preferring quiet lagoonal waters with little current. They are dependent on these Acoel flatworms as their primary food source, so when the worms are gone, the nudi will be also.
Even with this nudibranch, it is difficult to reach total biological eradication unless you have enough nudi's to put that kind of pressure on the flatworm population. I have considered breeding them for a while, but there is the issue of feeding them. Somehow although I know that the acoel flatworms don't actually do anything to the tank, their nuisance presence in the same proximity as the reef displays here makes me a bit apprehensive.
If the conditions are changed so that there is little to make the biotope attractive to the flatworms, the blooms will usually subside, even completely disappear. This usually means a change in both the conditions for the system as well as a change in husbandry. These flatworms generally need very slow current on a bottom with some form of substrate. They need a good strong source of light for their zooxanthellae (oh yeah, did I tell you they were photoautotrophs???), as well as a source of nitrogen or detrital materials. Blooms usually start in areas where the tank has accumulations of detrital material and decomposition has already begun to release the nutrients into the substrate. These flatworms then utilize these substances and will "sun" themselves to drive their photosynthetic mechanisms. Reproduction then occurs via fission, and may occur quite rapidly. I have seen tanks with the right conditions have an introduction of flatworms from an outside source and the bloom develop in less than a week, to the point where the entire substrate is covered in a sea of tan with red dots. The flatworms do not kill the corals that they rest on, they don't even eat the live coral tissue (although they may utilize the mucus for a food source), but they will block enough circulation and light to the coral that it dies from suffocation or loss of light source.
See
this post at the Sea Slug Forum and related links for more information on the Acoel flatworms.
