These are one of my favorite animals to keep, unfortunately Christmas tree worms are not easy to keep and require
phytoplankton at least twice a week to live any length of time. The larger the tank and the larger the
refugium the better.
I agree with a previous poster that they can be kept without a host coral, although the pacific ones tend to do better with them. I have not kept pacific porites before so I can't comment on that. But I can share what I've found about christmas tree worms.
1. They are filter feeders and the size of the food they filter and eat depends on their size. So if it is a very small worm it probably feeds more heavily on
phytoplankton. The larger worms may eat zooplankton, but what they eat is really unknown. Read this article for more info:
http://www.reefs.org/library/article/r_toonen21.html
2. Some may reproduce in reef tanks, but I have not seen a study that says they do yet. What is likely happening in cases where people report them "breeding" in their tank is that a very small worm has now grown into a worm large enough to notice. They can be very long lived animals and grow slowly. More information can be found here:
http://www.advancedaquarist.com/issu...002/toonen.htm
To quote from the end of the article: "However, our dismal success rate with these animals for more than a year or so in the aquarium suggests that we are failing to provide them with anything approaching ‘proper’ care! That means we cannot delude ourselves into thinking that the animals died of old age if they fade in our aquariums within a year or two (no matter how comforting we may find that excuse), and that is why I suggest they be avoided by any but experienced aquarists who want to experiment with maintaining these beautiful animals."
I hope to find proof that these animals can breed in the aquarium, but so far I haven't found it. I have put several homemade rocks in my tank that contains my specimens and I hope to find one growing on one of my homemade rocks in the future. So far 11 months into keeping them I have not seen any new ones on my homemade rocks.
3. Since these are potentially long lived animals (10+ years), I would not consider anything less than 3-5 years a "success" in keeping them. As with many other invertebrates they can slowly starve over a period of a year or more.
4. If you want to keep them, I think phyto is a requirement, at least twice a week, preferably more. The amount of phyto or zooplankton generated by a
refugium is probably not even close to enough.
5. I started off with 7 specimens in my tank. I did not feed phyto to my tank for about 5 months and one of them perished at the end of that period (I did not know they needed phyto as they call came as hitchhikers on rocks). Another one perished in a bad
salinity accident on my part. The other 5 are still alive 11 months later and appear very healthy. I feed my tank a 1-2 cups of phyto every 2-3 days and I also add selecon and
DT's oyster eggs that MIGHT be small enough for them to feed from(no proof). I also have several species of snails that broadcast spawn in my tank and that might add to their food supply, but it is unknown.
6. It is a common misconception that you can target feed christmas tree worms phyto. According to Dr Shimek it overwhelms the feeding mechanism and most of the phyto is far away from the worm before it can clear its "mouth" and resume feeding. This is why it is recommended to just feed phyto to the entire tank and give the worms time to feed.
OK, enough boring info right, here are some pretty pictures of mine:
Brian
USA 
V-series Productions 
icon under there name and give them Reputation points
I REALLY need to get better at being concise.