How quickly can acans become photoinhibited

[lyrano]

I've got a beautiful acan frag that I picked up from the LFS on Friday. It was doing great on the tank floor in a moderate flow area - until the LFS crew came by on Tuesday for the water change. They moved it to the top of the rock work, which put it in a high flow area, about 6-7" below my LED's. I'm not sure if it was an accident or if they thought it was a better spot. Either way, I didn't notice it until hours later, and it looked a bit receded. I moved it back to its original spot, but when I got a closer look yesterday, I was shocked to see severe tissue recession on 3 of the 4 adult heads and the 4 baby heads were shrunken, with only 1 head left that can still eat. I've been feeding it daily since then. I'm wondering if those few hours under the lights could've caused all that damage, or if I should be looking elsewhere for the problem. This is really frustrating for me.

[brixo]

It's definitely possible that the sudden move to the top caused the damage. I mean, going from moderate flow to high flow and being right under the LEDs must've been a huge shock to the acan. I'm just glad I caught it when I did and was able to move it back to its original spot. I'm planning on talking to my boss about it and asking him to have a word with the LFS - they really should know better than to move corals around like that. If the worst happens and the acan doesn't make it, I expect them to replace it - it's the least they can do.

[redvolt]

I'd just tell the maintenance guy myself if I saw him - please don't touch that one coral, I'm pretty sure they'll get the message. I do maintenance too and I move corals off the floor because clients don't like seeing them down there, but I get why you had it there. Acan's can handle high light, no problem, but that kind of drastic change is a different story - it sounds like your coral got seriously burned or something, like an LPS that's not happy.

[lyrano]

I've got to agree, it does seem pretty coincidental that this happened right after the LFS crew moved my acan. I mean, I've had it in that spot on the floor for a while and it was doing great, but then suddenly it's relocated to high flow and intense lighting and it's getting severely damaged. It just seems like that drastic change was too much for it to handle. I've got some pictures of the damage if anyone wants to take a look...

[lyrano]

I'm still trying to wrap my head around this whole ordeal. I've got some before and after pics of the acan, and I'm just hoping it can recover from this. Do you guys think it's okay to keep it in its original spot, or should I move it to a more shaded area to help it heal? I'm not sure what its chances are of bouncing back from this, but I'm crossing my fingers it'll make it.

[storm9]

I think it's got a good shot at recovery, the remaining bits have some nice color to them. I had a similar experience with some acan frags I picked up from an LFS a couple months ago - they were all bleached out, but I got a good deal on them. Only lost one, the others have colored up and are opening up nicely now.

[rileyon]

Looking at your pics on my phone, I'm having trouble making out the details, but it seems like there's still some tissue present, which is a good sign for recovery. A sudden change in lighting extremes can definitely cause deep polyp retraction, I've seen it before.

You mentioned tissue recession, but did the tissue actually flake off in pieces or strings? That would be a dead polyp. On the other hand, if it just puckered up and retracted into the skeleton, it's not necessarily dead. I'd keep it in low, indirect light for a bit and monitor its progress, gradually increasing the light exposure over time. Given that you were able to move it back to a safer spot within a few hours, I think recovery is definitely possible.

[lyrano]

Thanks a ton everyone, I really appreciate all the advice. Reef frog, I didn't see any tissue flake off or anything, so fingers crossed that's a good sign. My impression was that the tissue had just receded/retracted, and I'm hoping that's what happened since I've never had an acan before. I've moved it to a partially shaded area now and I'm going to keep feeding it a bit each day. I'll also have a word with the maintenance team from the LFS, let's just say I'll be telling them to leave my corals exactly where they found them from now on. Keeping my fingers crossed that it'll recover okay.