Took over a 18p gallon tank after my buddy killed everything on acciendent. He is moving and doesn't have room for tank. I kept the rock. Changed the sand. Anyways. I've been noticing these tube worms and was making sure they are okay. I've done a little research but cant find pics of these! Are these good to have? they are all on the rocks. dont see any in the sand. Never owned a salt water tank but I've always loved them so new to the hobby. Active scuba diver! Please help!

Their numbers will basically self regulate based off how much extra food there is available in the tank. So if you don't overfeed their numbers will stay in check 

