Hello all! I am new to keeping a saltwater tank. I just added a emerald crab into my tank. I saw the crab on my starfish on the glass and I thought it was attacking my starfish so I removed it from the starfish. After a few hours I checked back and the crab is right back on my starfish. I'm just not sure if I should be worried. I do have algae higher up on the glass because of my snails so I'm not sure if that's what he was doing. Im just not sure if its normal since i cant really find anything on it.