What could be eating my Coris Wrasse?

[The Life Aquatic]

One time I can handle, but twice...

Story goes, about 2 months ago my Yellow Coris Wrasse went missing. I know sometimes they'll disappear for a day or two so I waited and waited and waited but 2 weeks later no sign so I went out and bought another one.

Now, the new one is gone (had for 1 month)

It's not my parameters. It (they?) didn't jump...top is fully enclosed. They did not get sucked into the overflow. No other fish are obvious candidates for eating them (all relatively small/peaceful) and I don't have anything obvious like an anemone that could have done it.

The only thing I can think of is something is getting them in their sleep. I don't think it's a mantis since 1) I've never seen one...although I do hear the occasional clicking however I think it's snails and 2) It would be eating everything, right?

Are there any other creatures that might make sense here? Any other ideas? It's crazy it's happened twice with absolutely zero issues to any other fish.

I should add I have a camera on the tank, and both times the Wrasse was totally fine the day prior...lights go out and they simply never returned.

 

[Purpletang92]

Serpent starfish when they get big will eat sleeping fish if you have any, what other animals are in the tank ?

 

[The Life Aquatic]

Serpent starfish when they get big will eat sleeping fish if you have any, what other animals are in the tank ?

No other animals (just fish) other than a few peppermint shrimp, cleaner shrimp, and quite a few hitchhikers but nothing nefarious that I've seen. I do have some brittle star hitchhikers but no large ones (that I've seen). The tank is a 180g so it's possible something is hiding but would be weird I haven't spotted it yet in the 7 months the rock has been in.

 

[Purpletang92]

Search the tank at night you’ll be surprised what you find, could be a crab also.

 

[krollins]

Maybe something in the sand is killing them while they are sleeping in the sand?

 

[The Life Aquatic]

Maybe something in the sand is killing them while they are sleeping in the sand?

Exactly my thought but what...

 

[The Life Aquatic]

I just found a pistol shrimp! In over 6 months I've never spotted it before. But I'm hesitant to blame him...my peppermint shrimp hangs out right by the pistol's cave and if he's not bothering to pick off the peppermint I have a hard time believing it took out two wrasses.

 

[krollins]

Exactly my thought but what...

Maybe a bobit worm.

 

[The Life Aquatic]

The plot thickens!

I added a third and everything was fine for a month but then one night I was investigating the tank and found it breathing heavy on the front sandbed, its fins looked a bit ripped. From that point I watched it tried to dig into the sand but have a hard time. Now, I do have a sandbed but it's a bit shallow and for whatever reason it gets pretty clumpy which seems to give them a hard time.

Was fine for another month, and then poof disappeared. I assumed I lost another one and should give up on buying them but then a day later it reappeared! However, it is clearly beaten up...torn fins, some damage on the body.

Either something is indeed trying to eat it, and it managed to escape (and go into hiding for a day?) or I'm thinking they are somehow getting stuck and hurting themselves in their effort to find suitable sand.