non-chemical flatworm control

Joylynn · Feb 11, 2012

My 20G long reef tank has flatworms. I don't want to treat it with a chemical because whenever I do my long-spine urchin looses all his spines and the flatworms just come back anyway. I've read in a few places that the flatworms will eventually die off - has anyone had any success just waiting it out with flatworms? There are no fish in it but I think its too small to add any fish that would eat the flatworms.

Dog Boy Dave · Feb 11, 2012

They dont hurt anything. They will die off if you eliminate their food. As you clean your tank up they do tend to disappear. I wouldnt worry about them as they have filled a niche and they are harmless. However, a 6 line wrass will often eat them if you dont feed him anything else. I still have a few in my system but my smaller Angels eat them when they can find them so i only see a few in real good inaccessable spots.

chestnud · Feb 11, 2012

blue velvet nudibranch will eat all of them.

Joylynn · Feb 11, 2012

Chestnud, doesn't the nidibranch starve to death after it eats all the flatworms?

Dog Boy Dave, I'm not sure what these flatworms are eating. My fish died a few months ago after I treated for flatworms and the urchin lost his spines (I think the spines might have poisoned the fish). I haven't been adding any fishfood to the tank snce then. I do add phytofeast for the fanworm but I stopped for a few weeks and it didn't have any effect on the flatworm colonies. My ammonia, nitrites, and nitrates are at zero. The tank has been up and running for 3+ years with no more than 1 small fish in it and it has about 25 lbs of live rock. The corals are all healthy and so are the invertebrates. There is zero nuisance algae since I switched to LED lights.

chestnud · Feb 11, 2012

Yes, he will die after eating the flatworms unless you have a friend that could use one, or a LFS store that has some FW.

Dog Boy Dave · Feb 12, 2012

Would take months not weeks for them to die off as they eliminate their food source. If you are exporting more than you are adding the tank will get cleaner and the cycle will change. If you are adding enough to increase or maintain then it won't. As for what they eat, diatoms or algae would be my guess but who knows? I know they have increased in my systems in the past if i allow the nutrients to increase. Takes a pretty clean tank to starve them out. Once again, they dont hurt a thing. They are toxic when you kill them. Many fish will eat them eventually.
On a personal note. Probably the biggest reef aquarium mistake i ever made was treating a large established tank for planaria with flatworm exit. This was in 2005 and I had recently discovered the other type of planaria as in Accro Eating Flatworms and back then they were kinda new. I dosed the tank with the flatworm exit and it imediately killed all of the harmles flatworms. Unfortuntely the 180 reef tank was about three years old and full of the harmless planaria. When they died they turned the water tanic brown. Withing five minutes all of the green corals were bleached white. All of the corals in the tank lost most of their color imediately. My fish began to show severe distress and their fins began to tear. I lost several. I did an imediate 30 gallon water change and added carbon. That stopped the fish dieing but it was a very bad way to start trying to save a tank full of accros from the newest pest on the block at the time. Oh and the flatworm axit had no affect on the bad flatworms. The story goes on from there for a couple more years but I still have a box of unused flatworm exit on my shelf. I did manage to save about ten accros from that initial collection but the ones that lived were more due to me leaving them alone in an empty tank than any thing I did to treat the intial investation.

Joe S · Feb 13, 2012

A lot of wrasses such as the pinstripe fairy wrasse are a good (and chronic) alternative to nudis or chemical tactics... They will also mow on fire worms.