Live Rock Critters

Question
Hey Jennifer, a few days ago you answered my questions regarding fish compatibility. I have now put together a list of fish that I think would go well together in my 18 gallon tank. Here goes: one lawnmower blenny, two pajama cardinalfish, and one (maybe two) firefish goby. I am now researching invertebrates and the possibilities include a cleaner shrimp and an emerald crab. I also came across the cutest little animal called a lettuce nudibranch that I am interested in finding out more about. My question regarding the fish is what types of food should I get? I know lots of variety if important. I'm thinking mysis shrimp, frozen bloodworms, algae wafers (for the blenny). Any other suggestions?

My main question for today is about my live rock. Its fascinating! Each time I look at it I see something new! I would love your help in identifying a few of the critters I've seen.
1. a very small starfish? It had five legs. It was completely white and its legs were about as thick as sewing thread. The diameter of it was about 1/2 inch.
2. I have discovered at least two bristleworms. I identified them through pictures online. However, I can not find a straight answer as to whether these are harmful or not. I did not see the entire length of the worms, but the diameter was about that of a pipe cleaner. Do you think I should leave them alone but keep an eye on them or just try and get rid of them now?
3. I also noticed several small creatures with at least three legs and a rounded, hard shell. They are about 1/2 inch long at most.

Also, I was wondering if there was a website which shows actual pictures of live rock inhabitants? It seems like when I Google "live rock organisms" the results only include forum discussions on them with only a few pictures (which aren't very clear).

I would appreciate any advice/help/suggestions you have!
Thank you,
Emily

Answer
Hi Emily. The fish you are planning on getting are great choices for your size tank! The crab and shrimp would also be a nice addition as well. Glad to see you are doing your homework. Are you waiting until your lights are off for a while and shining a flashlight over your liverock? If not this will open up an entire new world! As for all the critters you are seeing, yes, I do know a very good website for you to use as a reference as to what you are seeing. Remember that there are tons of stuff that can come in on liverock and you may not find an exact match every time. These pictures are used to aid in identifying and colors may be varying even within the same exact animal.
http://www.chucksaddiction.com/hitchhikers.html
Check out this site. I think you will find it as fascinating as I do.
As long as you feed a variety of frozen meaty marine food your fish will be in good shape. You may want to stay away from algae wafers however, they tend to cloud up your tank quite a bit. A better alternative would be algae paper. This food is sold under different brand names but it is all basically the same. It is a thin sheet of dried seaweed that you place in your tank either under a small rock or with the use of a veggie clip so it won't float around your tank. All your fish will nibble on it and it won't mess up your tank. It is made up of actual seaweed and is very nutritious. You may want to look into purchasing a supplement called Selcon to use with your frozen food once or twice a week. It just provides a little extra nutrition for your fish.