My tank has been fully cycled and is a little over 1 month old. I have an Ocellaris clownfish that I have only had for about a few days now. He is healthy and eating fine. I know I shouldn't add another fish for a couple weeks and I wont. I am really interested in purchasing a Diamond Watchman goby. Do they need a more mature sandbed since they sift it so often? How long should I wait until I add one ?