Well, given the description from Jawbone, I somehow doubt that we're all talking about the same thing. The true Christmas tree worms (
Spirobranchus "giganteus" - I put this in quotes because it is not really a valid species name, but rather a species complex for which the taxonomy has yet to be worked out) only grows about 0.2 mm diameter per year in the wild, and the maximum under ideal conditions seems to be about 1.0 mm per year. So, even if we assume that the growth rate in your tank is around the maximum ever observed in this worm, there is no way that one of these worms can grow from juvenile to adult size in less than a year.
In fact, estimates of time to reproductive maturity in the wild are between 5-10 years. Also, these worms reproduce via mass spawning that produces long-term feeding larvae which are very difficult to raise in captivity. The larvae need phytoplankton concentrations on the order of 10,000 to 100,000 cells per ml of culture water in order gain enough energy from feeding to complete their development and metamorphose into an adult worm. During the several weeks that these larvae are swimming in the tank water (even assuming that there were anywhere near that concentration of phytoplankton present) they would still have to avoid being eaten by corals, filters or protein skimmers. Thus, it is highly unlikely that these animals would be able to reproduce on their own in any aquarium, and to date there has been no report of successful reproduction by
Spriobranchus without intentional larval culture (I explain what is involved with this in the
Home Breeders Guide)...
I'm glad to hear that yours are doing well, and that you enjoy them, Jawbone, but I have to assume that we're talking about different critters here. If you have these worms PoJohnny, then you shouldn't be expecting to see any babies any time soon. It is also probably worth keeping in mind that most suspension-feeding marine invertebrates are adapted to periods of low food availability, and that they are capable of slowly digesting themselves to wait out periods of low food. Because of this, they are able to last an amazingly long time without sufficient food in an aquarium. It is not unreasonable to expect that a well-fed and healthy worm collected from the wild could last 6-12 months in an aquarium while it slowly starved to death.
I don't mean this to sound at all discouraging, but I just want to make clear that the animals need to be fed the right size and quantity of food to survive long-term in the aquarium if Dustint decides to get some....
Rob
[ February 25, 2002: Message edited by: Biogeek ]</p>