Movement is key to a tank, you want your water to cycle, keeps the fish happier too, try off settign them if you can, half them switch a few times a day to get a real realistic effect. Thats what i do in my 55 gallon. I got 2 400GPH in my one tank switching ever 6 hours or so to change the flow of water. While i got the rest of the pumos cycling the water from side to side. IT is a sick setup, i will take some picks.
As for hiding. I put them behind some large rocks in the center hooked to my endergravel. One facing each way. Cant even see them.