ID ? video of invert

[Newstead]

Please take a look and help me ID this guy. Never comes out completely, but when I feed the goby mysis, a few legs peek out, grab a shrimp from the baster and retreat. Less than .5 inches across (the entire rock is only 3x2 inches and came from Vietnam). I have it in my QT with a ywg and an emerald crab.

Https://youtu.be/CUn2YBDhNvQ

Thanks!

 

[Betta132]

Those aren't actually legs, they're bristleworms. Scavengers who prefer to stay at least halfway in their hidey-holes so they won't get eaten.
Despite what some people will tell you, they're good. That particular kind is basically a spiny little earthworm, and they're great scavengers. Just don't touch them- the spines will break off and stick in your fingers. As long as you don't touch them, they're perfectly harmless, and they'll help keep your tank clean by eating all of the gunk and bits of food that nothing else can reach.
They usually stay under 2" long, but if you feed your tank far too much, you'll either get five gazillion tiny bristleworms or about two dozen 4-6" ones. Even then, they're harmless, though some people don't like the look of them.
They're actually pretty good food-level detectors. If the amount of bristleworms in the tank is noticeably increasing, you're overfeeding.

 

[Sugar Magnolia]

Looks like the back legs of a crab to me.

 

[ginpang]

Chlorodiella sp ?!

 

[Calappidae]

looks like the back legs of a crab to me.

+1

Crab on a sideways angle crawling into a hole.

 

[Sugar Magnolia]

+1

Crab on a sideways angle crawling into a hole.

Or partially out when smelling food. These guys are nocturnal so your best chance of seeing the crab is when it ventures out of the rock in the wee hours of the morning when its out scavenging for food.

 

[Newstead]

Thanks for all the help. I had decided crab as well, but in the video since I can enlarge it the body appears small, round and almost a fuzzy black. On another forum someone suggested a type of sea spider. Going to see if I can get a pic or video of him during the night if I can catch him out!

 

[Shawn O]

Leg's move like a spider's. Can you take a better, more stable video?

 

[Newstead]

I will try - the legs comes out maybe once every other day, I feed him a mysis shrimp or pellet and he is gone!

 

[Shawn O]

You could try tying a larger piece of shrimp to a rock with fishing line and place it so that the thing needs to come out farther to get it.

 

[Newstead]

Good idea ... I may try putting his shrimp a little farther from his hole each day. He didn't come out for two days but last night when I was feeding the goby and crab, here came 4 arms for his meal ;-)

 

[MJV0103]

That's kind of creepy

 

[Newstead]

It almost is ... but each arm is only 1/4 inch long.... if they start getting realllllly long I am going to be worried ;-)

 

[Newstead]

Finally solved the "mystery" - it is a crab. Weird little guy - never comes out of the 3x2 inch rock except for a mysis. Attaching pics and the url for a video I finally grabbed - sorry about the Price is Right background noise and the few seconds of blur at beginning.

Https://youtu.be/4fl3gnne7BE

 

[Sugar Magnolia]

With those sharp claws it'll definitely be a problem in the future.

 

[Newstead]

That is what I am afraid of - and of course I feel responsible for it. It is still tiny and stays in its little rock, but I am going to have to figure out something in the future.

 

[Betta132]

Do you have a sump or refugium it could live in?

 

[jraker]

throw it in a refugium if you have one. it will be a problem when it gets to be 2 inches long.

 

[Shawn O]

I like it, it's different.

 

[Newstead]

Unfortunately, I don't have a sump, and Shawn, I like it too! This is in what was my QT, a Fluval Spec 5. I bought the piece of live rock with 8 to 9 blue mushrooms on it, but there were so many hitchhikers in it I fragged 4 mushrooms off of it finally for my biocube 29 and left the rock in the fluval. In the 6 weeks I have had it have seen a o. Clam come out, and slowly make his way to the larger rock in the tank, plus micro feather dusters, pink foraminiferan, sponges, etc. Then I purchased a ywg for the biocube and my female clown pitched a fit and kept chasing it, so it went back to the QT. Next step, and the fatal one, we are talking about getting a large tank (husband wants 125 gal, the maintenance lady -me- says 65). So this guy will probably live in the sump there as long as he behaves himself for now. Hoping feeding him will keep him civil for a whike? His rock and the goby's rock are on opposite ends of the tank and so far he has never ventured out of his rock, even at night.