Amphipod predation on Birdnest?

[NatureNerd]

For the last two months I have found small strips of tissue cleared off both my Birdnest (Pink Seriatopora and Ponape) coral colonies. At night I see large (1/4 inch long) amphipods (Grammarus sp, I think) at the site of the damage. They appear to be eating the coral flesh. No other SPS corals have been damaged including a ORA metallic green birdnest.

The damage occurs always at night and mostly mid-branch, but sometimes base or tip. The tissue loss sites are 1/2 long and about 1/4 wide strip. I have always had lots of copepods, amphipods, and other small bugs but nothing has damaged any SPS's before. I have also never heard of a species of amphipods that eat corals.

Any advice is much appreciated.

Livestock list: 2 Occ clowns, Tailspot Blenny, Purple Firefish, 2 skunk cleaners, small two-spot tang, and DF pipefish. The only thing out at night are the cleaners.

 

[mordinad]

Nothing helpful but maybe comforting. I have amphipods digging into some of my acros. They dig inside then lift up the skin. Some receding but after 2 weeks it's ok and there looks to be a symbiotic relationship.

 

[mallorieGgator]

They are possible zoa preditors as well. Since I introduced my Lubbocks Fairy wrasse the amphipod population has decreased significantly and my zoas are always open and happy now(also, either a crab or the amphipods ate almost and entire zoa skirt about 3 weeks back)

 

[NatureNerd]

Thanks. Anyone else? Is it even possible that it is an amphipod? Could it be some other predator on this type of coral?

 

[Reef Bass]

The usual reply to "there are pods on my coral" is that they are cleaning up dead tissue, not creating it. Your description is specific enough that I'm not sure that's the case here. The usual causes of acros suddenly missing chunks or flesh are crabs (maybe shrimp here?) or larger worms (eucinid).

 

[jc-reef]

The usual reply to "there are pods on my coral" is that they are cleaning up dead tissue, not creating it. Your description is specific enough that I'm not sure that's the case here. The usual causes of acros suddenly missing chunks or flesh are crabs (maybe shrimp here?) or larger worms (eucinid). ......or a pathogen or element deficiency in your tank (especially birdsnests).

 

[NatureNerd]

Thank you, I will keep looking for another cause. I have 4-5 species of "bugs" present in large numbers in my reef. It is only the larger curved back species (Grammarus) that seems to be on those corals within minutes of the lights going off. Usually 2-3 at each damage spot. They are there all night.

All other acros are doing great with excellent growth and good PE and color. I did see a nickel-sized crab in the tank a few weeks back. I suppose it is possible he does a quick dine and dash. Just happens to like BN's?

I have been checking on the tank every hour or so through the night to see if anything else is on these two birdnest. I will keep up the hunt a few more nights.

Lack of some trace element is hard to find, a pathogen seems plausible (only one species affected). Thanks again.

By the way, this is a 15 yr old tank, I have been keeping mixed reefs for 25 years. I have not seen anything like this before. It has me stumped.