Elimination of red planaria

[AndrewB]

The following is a description of a protocol used at SCALES Tropical Fish Warehouse for the elimination of red planaria in a retail aquarium system. It is not intended as a recommendation for strategies to eliminate red planaria in the home aquarium.

 

Introduction

 

Red planaria (Convolutriloba retrogemma) are simple animals that host a photosynthetic dinoflagellate similar to those hosted by certain corals, anemones, etc. The actual photosynthetic organism is not the same species but the function is identical. Red planaria do not rely on outside food sources, as the dinoflagellate provides all of its nutritional requirements. In a closed coral reef system they may be imported on live rock, sand or coral specimens. Red planaria are capable of asexual reproduction through budding, so only one is required to initiate an infestation. Often they reach "plague" proportions where every surface is virtually covered with the planaria. Generally, even in extreme infestations, the presence of red planaria is not dangerous to the other organisms in the aquarium. It is speculated that extreme infestations may damage corals by interfering with light absorption of the corals. With massive infestation the likelihood of individuals dying and releasing toxins into the aquarium system are enhanced. Whatever the imminent dangers, there

[djcerna]

Thanks AndrewB!

[trble81]

Andrew,

 

You said that the standard dip method didn't remove them and that the freshwater dip was very effective but risky due to coral intolerance, what do you suggest as a treatment prior to the addition of coral into a home aquarium?

 

 

--Mike

[zotzer]

Wow...thanks for an extremely informative post!!

Tracy

[lanman]

Excellent information!

 

Can anyone say which corals and other organisms are likely to be damaged by a short freshwater dip? For situations like I had, this might be preferable to my own protocol. Certainly less expensive, and probably more reliable based on the efficacy with which the fresh water appears to destroy the worms. i.e. - not having to rely on the EXIT to work.

 

I transferred everything in my moderately-infested 45-gallon tank to a 58-gallon tank. I gave everything a 30-second rinse in tank water to shake off loose planaria, and then a 30-minute soak in tank water treated with EXIT. I replaced the sand bed completely, except for a few cups that were treated with EXIT. Everything survived the treatment/transfer except the flatworms.

 

bob

[AndrewB]

You said that the standard dip method didn't remove them and that the freshwater dip was very effective but risky due to coral intolerance, what do you suggest as a treatment prior to the addition of coral into a home aquarium?

 

The trick with dips is that you are targeting a wide variety of undesirable hitch hikers. As far as red planaria go, it is likely that a dip in a stronger solution of Flatworm Exit or a freshwater dip will be equally effective. I was specifically commenting on "Flatworm Exit" used as a treatment in an established system, not a prophylactic dip. The problem with using a lot of the dips, especially when comparing anecdotal evidence posted by home aquarists, is by sheer statistics it is likely that many of the situations where it does not work may be due to user error or other outside factors. The other issue is that when you compare the traffic in coral specimens in a retail store where hundreds of pieces may transfer into and out of tanks every month, statistics will also dictate that it is more likely that a bug make it through sterilization protocol than for the home aquarists who may transfer, at most, dozens of pieces per month and usually much less. In both cases, it's not that the dip doesn't work, it's that the dip kills 97% or 99.9% or whatever the number is (I honestly don't know) of the red planaria. With enough statistical sampling the product will fail eventually to kill all of the red planaria for somebody. Freshwater dips, however, will kill 100% of red planaria when properly executed. Again, the issue of user error and other factors may come into play. Additionally concerns besides the red planaria may not be addressed by the freshwater dip.

 

Can anyone say which corals and other organisms are likely to be damaged by a short freshwater dip?

 

We dipped zoanthids, corallimorphs, Sarcophyton, and Sinularia with no damage to the corals. On the live rock, coralline algae was unaffected. I also talked to Almon and he has dipped many SPS corals similarly with no ill effects. I'm sure there are resources online where more coral species have been investigated. My concern would be soft and LPS corals that have very thin membranes like bubble corals, Cynarina, colts, etc., where the osmotic pressure of the freshwater dip may damage the delicate tissue. If someone were to try these the corals should probably be encouraged to withdraw as much as possible before trying the dip. This is hyppothesis though; I haven't tried and haven't talked to anyone who has tried more delicate corals.