Originally Posted by
ifirefight
http:///forum/post/2622012
Can somebody please explain what these spiders do and how I can tell if I have any. Do they "eat" the zoa and it disappears or do they eat it and it stays closed...do they eat the stem or the polyp area? Will I see them with the lights on or only after lights out? Thanks
Spiders aren't just a problem for zoas... They will prey on just about any soft coral in your tank, but it seems most experiences are with zoas. There is also a type that feeds almost excuslively on aiptasia, but I'm not sure how common these are (not common enough, unfortunately
)
As previously mentioned, they sometimes embed themselves underneath the mucus layer of the zoa, which makes them very difficult to get at and even harder to spot. Typically, they stick towards the base of the polyp or along the stalk. This will cause the indidual polyp to close up and usually stay closed.
From what I have read, they actually bore holes into the polyps and eat from there. Since they are chelicerates, they do not have jaws to physically chew the polyp, so they use a probiscus to eat the polyp basically by siphon as they're hosted outside of them. There have also been cases of the males depositing the eggs inside the polyps in this same way, but from there, the gestation period is more or less unknown.
Also from what I've read, they are more active at night, and can be identified using the red light technique. FW dips can weaken them after a few minutes, but they will still show resistance against removal (via picking off with tweezers).
Hope this helps...