Who Gives A Fish Forums

I'm having a weird issue with my plate coral - whenever the lights kick in, it starts closing up shop. When they're off, it's somewhat inflated with about half its tentacles out, but as soon as the lights turn on, it deflates down to its skeleton and pulls most of its tentacles in. Has anyone else experienced this?

I'm running one 250W metal halide and four T5s - the coral's sitting on the sand bed, 18 inches down, with the lights 4 inches above that. I've also got a short tentacle plate coral that's thriving under the same lighting, so I'm stumped.

I'm curious, what's the size of your tank? Have you recently tried feeding the coral? It's possible the coral is getting too much light. I'd suggest moving it to a different location for a bit, at least a week, to see how it reacts. It doesn't have to be in the shadows, just somewhere with less intense lighting. Good luck.

It's a 46 gallon tank. I've tried feeding it, but it doesn't seem interested - it just holds the food for a bit before letting it go. I appreciate the suggestion, I'll definitely try moving it to a spot with less intense lighting to see if that makes a difference.