Recently bought a couple of yumas and put them in my qt tank. My qt is a 90g with 2x175 mh and 2 110 vho act. They moved of their rock and I placed a piece of rock in a plastic container and put them in the container so they could attach but they seem to sliding under the rock in the container. I've put them in different location and diff. flow but they love to move. What's the best way to attach these buggers? Thx in advance for any replies