A few ? Velvet nudi and red flatworms

[graveyardworm]

I have had red flat worms in the past and thought I had conquered them, with manual removal and FWE. It seems that there are always a few left to reproduce no matter how large of a dose or frequency of dosing.

I've decided that these guys are natural part of the reef, and while large populations are unsightly and a mass die of potentially bad I think I'm going to have to let them persist and look to other means of control rather than continueing to try eliminate them.

The Velvet Nudibranch (so called) chelidonura varians is a natural predator and really cool looking to boot. Anthony Calfo had made comments to the effect that these guys are now being aquacultured and have become a more viable means of control.

So my questions are:
1) Is there any data related to what size tank or how large of a population is required to maintain a VN? How much LR per individual?
2) How toxic would the VN be if it died in a 300 gal+ system?
3) Flatworm repoduction, are they a broadcast spawner so their offspring may actually feed corals and other filter feeders, or do they reproduce through fision as I've read and would'nt have a ny benefit to filter feeders?
4) Exactly what is the red flatworms role on a natural reef?
5) In the link provided lifespan listed as 3 months, is this in the wild or an aquarium setting?

 

[graveyardworm]

For anyone unfamiliar with these here's a link with pic and description.

http://www.marinedepotlive.com/velvet-sea-slug---chelidonura-varians-inverts--nudibranch.html

 

[kmk2307]

graveyardworm,

I have heard nothing but sad experiences with Chelidonura varians in captivity. I imagine that the density at which Convolutriloba flatworms are usually found when they are present at all in marine aquaria is sufficient to keep an animal well fed. I doubt that one C. varians kicking the bucket in a 300 gal tank would be noticeable. A friend put one in his 65 gal reef and never saw it again but didn't notice any ill effects.

There are a lot of literature papers on Convolutriloba flatworms. I don't believe they are broadcast spanwners and I think sexual reproduction is rare. Try searching google for Convolutriloba and Convoluta (which i think is the former name of the genus?). Also use Tetraselmis symbiotic acoel flatworms for search terms. I believe 3 months is an estimate of the duration of the "bloom" of the flatworms. I don't know its source but I think that time can be considerably longer. Since these worms reproduce asexually by splitting in 2 usually, an "individual" in a sense may live a very long time, even if only half of it lives.

HTH,
Kevin

 

[graveyardworm]

Its been close to year since I last noticed the flatworms at that time I treated the tank with FWE. It wasnt until I moved some pieces of LR from that display to my new one that I agian noticed the flatworms. I've been siphoning them now for about a week sometimes only one at a time as I see them. So the population is small and under control for the time being. I did a google search on the C. Varians and got alot of hits and alot of info although most of it was at least a year old and not really geared towards keeping an individual in captivity, perhaps because they are noy very successfully kept.