Hydnophora Reproduction

Hydnophora grandis

I discovered that my Hydnophora grandis coral had what looked like a broken branch. The skeleton was clearly fractured and the wounded limb swayed in the currents, attached to the host by a thin tissue. Here we see the dangling limb. It is attached with a small segment of translucent tissue. You can see the skeleton above and below the middle of this tissue. How the skeleton broke is a mystery. Considering how thick these branches are, and the fact that this limb was away from the rocks (no snail could have done this) the only thing I can think of is that a fish hit it hard. I did not notice any tissue damage to the effected branch and none of the fish showed any signs of a wound. The other possibility is that the coral self fractured the skeleton - is this possible?

I pinched off the branch and attached to a small piece of live rock using Ross's Super Glue Gel. It is doing fine, and will soon encrust the live rock and begin to grow new branches. The host coral colony is fine and continues to grow.