Newbie with ID Question - Marine "Ant Trap"?

newave · Jun 10, 2020

Hey, folks!

This is my first time posting, so I hope I'm in the appropriate space for help with ID'ing.

This morning, as I was inspecting my tank I noticed a sort of "ant trap" in my fine sand. I tried to do relevant Google searches but couldn't find any info.

I have noticed no feelers or anything extending from the hole yet, just a dark speck.

A bit more info: Tank was set up 28 days ago. Live rock and accompanying hitch hikers - brittle star, 2 snails, 3 hermit crabs, pinapple sponge, what I believe to be pseudocorynactis, possible baby tube worms (responsive to touch, will probably ask for help to ID soon if I can't nail it down myself), probably bristle worms, are the only inhabitants.

I've been wondering all day, what could this thing hiding in my sand be? Any knowledge shared is appreciated!

Happy reefing, all!

Auquanut · Jun 11, 2020

Welcome to R2R! You may have to use a flashlight after lights out to get a look at it.

newave · Jun 11, 2020

Thanks, Auquanut! I'll do that. I feel like I've gotten super lucky with my hitchhikers - hope this one is a good guy, too!

HOOPDEEZ · Jun 11, 2020

Bobbit worm!

Just kidding I’m not sure. Your sand looks very sparkly, is it silica sand?

newave · Jun 11, 2020

HOOPDEEZ said:
Bobbit worm!

Just kidding I’m not sure. Your sand looks very sparkly, is it silica sand?

Oh GOSH! I was just showing my family vids of bobbit worms in action earlier in the week. They're the stuff of nightmares!

Thankfully, it turned out to be a lost/presumed deceased cerith snail appeared, peaking out from the indentation shortly after I put a sinking pellet nearby/lights out. I had forgotten they will burrow. >.<

As for the sand, it does contain silica - just a bag of basic Caribsea Super Naturals sand.

Thanks for trying to help me figure this out, folks!

Billdogg · Jun 12, 2020

Just a note for future night viewing - if you use a red light the inhabitants for the most part won't be bothered by it so you can watch them do their thing more easily. I got a small LED flashlight that has both white and red - maybe $10 at HD/Lowes.