I have a 55 gallon tank that I have had for a month and a half. I have three damsels, 15 pounds of live rock, argonite substrate, and six snails( 4 astraes, and 2 turbo). When I fist placed them in the tank a few weeks ago, they were all crawling all over the live rock, eating stuff off of it and looking like they were having a good time. My trites and everything is good. Now, they have all moved up to the very top of the tank,some almost comming out of the tank. They have been up there for the past couple of days. And they dont seem to want to come back down to the rock or substrate. Does anyone have any ideas of what this might be about?