worms in my tank and dead fish?

[ravenhawk]

Ok about 1/2 -2 months ago I bought two blue leg crabs an emerald crab and two small pieces of live rock for my 55l tank two weeks ago one of my damsels died and a week later the other tow were dead as well. The first damsel, a 3 spot, was rubbing on the rock a little but the other two seemed to be fine. The morning before one of the others died I noticed small whitish spots on the fins but they looked alot like air bubbles. After they were all dead I began to see small (1/8- 1/4 inch ) white worms swimming in the tank. Do I have ich or is something else going on?

 

[ravenhawk]

Thanks Terry I have started to do periodic small water changes maybe I will try one larger one all of my nitrates, etc. are normal so thats good. Do you have any idea where the worms could have come from? the lr maybe?