SPS eating Melanurus Wrasse?

[Auroraz]

I’ve had this Melanurus wrasse for about 10 months with absolutely no issues, and I’ve had this coral for around 6 months.

The other morning, I was surprised to find the Melanurus actively picking at and eating the coral. I’ve never seen this behavior before, and nothing has changed recently in the tank.

Has anyone else experienced a Melanurus wrasse suddenly developing a taste for an SPS?

I've heard that sometimes wrasses may go after a coral because they're actually hunting pests on it. However, I haven't introduced anything new to the tank recently and from the pictures below you can see it literally mowed the coral down rather than just picking at something on it.

and here's how it looked like couple of months ago:

 

[Arkayology]

I've never seen that before. You are sure there are no pests on that or other acros?

 

[Auroraz]

I've never seen that before. You are sure there are no pests on that or other acros?

I'm not sure to be honest. I'm only assuming that because all of my corals look healthy to me.
Is there an easy way to tell whether pests might be present?

 

[Reefing102]

Never seen that either but I definitely misread the title as your SPS are eating your wrasse lol

 

[BryanM]

Near as I can tell they won't eat SPS, so it is likely he is hunting pests like flatworms or something.

 

[Biokabe]

I had a melanarus for 5 years and never any coral aggression. I'm not sure if corals are even digestible by them.

They are, however, voracious predators of copepods, amphipods, nematodes, nudibranches, and any other tiny inverts, along with larger inverts like shrimp and crabs.

Most likely you have some kind of little bug - not necessarily a pest, though it's entirely possible that it is one - that has been living on or around that coral. Flatworms are an obvious candidate, but it could also be any of a variety of little copepods. And your wrasse is preying on them. Since he doesn't care about preserving your coral, he might be damaging its flesh when he strikes.

 

[Auroraz]

Thanks, everybody.
Is there an easy way to find out if I have flatworms?

 

[Alexander1312]

I would love to take it off your hands to have it eat my flatworms, but you are a bit far away from me :).

 

[billyocean]

Thanks, everybody.
Is there an easy way to find out if I have flatworms?

Dip it in kcl (potassium chloride)

 

[Biokabe]

Thanks, everybody.
Is there an easy way to find out if I have flatworms?

Without taking it out of the tank:

Wait for the middle of the night. Take a weak light and shine it on your glass. If your tank has flatworms, you'll likely see tons of them on the glass.

Here's an image I pulled off of Google of what they look like. They are typically tiny, but a bit larger than copepods - large enough that you can see some structure on them.

If you don't see them on the glass, it doesn't mean you don't have flatworms - but if you do see them, you definitely do. Not all flatworms are created equal - some of them actively eat corals, while others just damage them because they crawl over them, blocking light and irritating flesh (and provoking hungry wrasses to strike the branches of the coral).