Saltwater Live Rock Question???

Question

I added 6 pounds of live rock to my 10 gallon saltwater yesterday. After placing the rocks, I noticed an anemone spring out a couple of hours later. Today I noticed a worm of some sorts about 2 inches long. And tonight I went in and cut the lights on after it had been dark for a while and noticed 2 black legs sticking out and moving out of a crevice in one of the rocks. After seeing me or the light, it quickly pulled itself back into the rock. Any clue of what this might be? I am new to this. Also, what else can I possibly expect to come out of just the live rock alone?

Answer 1

The anemone is most likely an Aiptasia (you can find photos in the links below or on the web). These are nuisance anemones and should be eliminated. My method to do this is to introduce a peppermint shrimp. After the shrimp gets used to your tank (about a week) it will eat them.

The worm is probably a bristleworm. These won't bother anything in the tank, and serve a useful function by burrowing through the substrate to look for food - this keeps the substrate aerated so pockets of hydrogen sulfide gas don't build up. You should be careful when handling your live rock with them in the tank though - the bristles HURT if you touch them! You shouldn't put you bare hands in the tank anyway, but use latex gloves when you clean and move items around.

The black legs are less obvious. If they're soft and flexible, it may be a small brittle star, or the mouthparts of a worm (some worms have mouthparts that look like brittlestar legs - I have two on a piece in my tank). If the legs are stiffer and jointed, it may be some type of shrimp or crab. If what the leg is attached to is larger than an inch, you might want to try and catch it to identify it - many crabs especially will eat small fish and other inverts. You might see if you can get a better look at it at night (go in the room with a flashlight after the lights have been off for a while) or make a cheap plastic trap and try to catch whatever it is. Here's a trap that's easy to make: http://www.floridadriftwood.com/fish_trap.htm - you may just want to pile up some substrate so it's easier for whatever this is to get into the trap. Just put some food inside and leave it overnight.

You never know what you might find living on the live rock. I've found macroalgaes, 3 kinds of shrimp, brittlestars, 2 other seastars, a sea urchin, a few kinds of snails, bristleworms, spaghetti worms, fan worms, peanut worms, sponges, tunicates, sea cucumbers, a crab, chitons, limpets, Aiptasia, a few corals, and some miscellaneous clams/bivalves. It can take months sometimes to know what "hitchhiked" in on the rock. And don't forget to check you filter pads before you change them - plenty of small shrimp get caught, and I once rescued a brittle star that was just over an inch from tip to tip (that was 4 months after I put the rock in the tank, and the first I saw the star). See the links below for help with some hitchhiker ID.

NOTE: Regarding the answer below mine, it's not a pistol shrimp that breaks glass, but a mantis shrimp. And both make popping or snapping noises.

And regarding bristleworms: http://www.reefcorner.com/SpecimenSheets/bristleworm.htm

Answer 2

If the worm is pink and looks hairy then it is a bristle worm, I have found them far from harmless. I have had one kill a clam and they can sting fish especially Gobies and Blennies that hide in the holes in rocks, the bristle worm hides in the hole and when the fish goes in they can sting.
I wait till the light goes out and then the bristle worms will come out and if I can I will take the rock out and poke in the hole to try and kill it or if the rock is near the bottom I use tweezers and grab it and pull it out, but don't touch them as they will sting you.
The anemone will probably be Triffid anemones, these you don't want, they multiply and sting fish, you need to get them out, you can buy Arrowhead crabs that eat them or you can take the rock out and as with bristle worms poke in the hole that it shrinks back into and kill it, if you can't take the rock out then try and do it with it in the tank, it may take a few attempts but you will get it.
The two black legs could be brittle starfish or crabs which you will not have any problems with.
I once got a Pistol shrimp, which you definitely don't want they can break the glass and attack the fish. If you hear a loud noise like gunshots coming from your tank at night then changes are you have one and need to get it out.
I have also got a small Cowrie that came out of the rock, these are harmless and help with cleaning.

Answer 3

That's why it is live rock. Plants and animals can go into a hibernated state. I have live rock that after I put it into the tank I had fan worms and a jelly fish come out. Most likely what is in your rock is crabs. No rock is the same if you are lucky you get rock with organisms living in them. You are lucky.

Answer 4

lots of invertebrates can be found in there but be careful because a predator might come out of there

Answer 5

worms, crabs and snails mainly is what I hear and they apparently multiply rapidly