Nocturnal and super fast!!

Girthrockwel · Jun 8, 2017

I work pretty crazy hours. I came in from work at about 2am and walked past the tank and thought is take a peek to see where the clowns were bedding down. I shined my cellphone light and cought a glimpse of something tearing across a rock and into a hole. My rock is all BRS reef saver except for one piece that I got from the lfs to seed the tank. The critter was on the live rock. I started googling trying to figure out what it could be but I didn't get a good look at it. So after a few minutes I went back and shined the light at the rock and there it went again. It's so fast that I still can't get a great look at it before it ducks into a hole in the rock. It's maybe 1/8 of an inch long, pretty small and I can't tell the color. The only other sign that anything might be living in the rock was one day I saw a puff of sand come from a hole on the side. I figured a powerhead blew it out or something. Now I wonder...

SashimiTurtle · Jun 8, 2017

Following, I'd love to see a picture.

Mikedawg · Jun 8, 2017

Girthrockwel said:
I work pretty crazy hours. I came in from work at about 2am and walked past the tank and thought is take a peek to see where the clowns were bedding down. I shined my cellphone light and cought a glimpse of something tearing across a rock and into a hole. My rock is all BRS reef saver except for one piece that I got from the lfs to seed the tank. The critter was on the live rock. I started googling trying to figure out what it could be but I didn't get a good look at it. So after a few minutes I went back and shined the light at the rock and there it went again. It's so fast that I still can't get a great look at it before it ducks into a hole in the rock. It's maybe 1/8 of an inch long, pretty small and I can't tell the color. The only other sign that anything might be living in the rock was one day I saw a puff of sand come from a hole on the side. I figured a powerhead blew it out or something. Now I wonder...

Copepod or amphipod?; if so a good score. Pretty common in established tanks.

Katrina71 · Jun 8, 2017

I was going to ask that too. Mine was elusive for weeks. I only saw something gray about the size of a pencil eraser. It was pods. Cool to watch building a little sand wall under gsp.

Girthrockwel · Jun 8, 2017

Well, I stayed up a little longer and got a better look at it. I had to let my eyes adjust as much as possible and provide just enough light so as to see but not alarm the critter. He's a tiny worm of some sort. Maybe 1/4 inch long. I was able to watch it scurrying around the rock, he'd go in and out of holes moving at a pretty good pace. I'm severely color deficient so I'll have to get the wife to help me with color. It kind of looks like a really tiny bristle worm from the pictures I've seen of them. It's hard to tell though as fast and small as this thing is. Is it common to see them that size?

Mikedawg · Jun 8, 2017

Girthrockwel said:
Well, I stayed up a little longer and got a better look at it. I had to let my eyes adjust as much as possible and provide just enough light so as to see but not alarm the critter. He's a tiny worm of some sort. Maybe 1/4 inch long. I was able to watch it scurrying around the rock, he'd go in and out of holes moving at a pretty good pace. I'm severely color deficient so I'll have to get the wife to help me with color. It kind of looks like a really tiny bristle worm from the pictures I've seen of them. It's hard to tell though as fast and small as this thing is. Is it common to see them that size?

Bristle worms are pretty slow movers and a usually pinkish in color; probably something else I would guess.
BTW, different opinions on value, if any, of bristleworms. I personally keep them as I like the biodiversity of a mature reef and they are detritivores.

Girthrockwel · Jun 8, 2017

Today I added a reef cleaners snail pack to the tank. The piece of live rock in question has some algae on it so I made sure to put a few snails on it. One of the made its way to the mouth of the hole that this critter lives in. It keeps popping out and touching the snail. I got some cell phone video but it's terrible. The wife is saying that it's brown or black. It has little antenna that he waves around out of the hole. I took a toothpick and put the point at the mouth of the hole and he checked it out a couple of times. It definitely seems long and thin. Super creepy.