I noticed when cleaning Filter Socks, I had quite a few Amphipods. I installed some Plastic Grommets in the Bottom side of some old Filter Socks, opposite the seam. Amphipods were able to escape, and Filter Socks, still were getting dirty on schedule. Now I have Copepods on the glass of all my Aquariums. Also seeing more Amphipods. Thinking about adding a Mandarin to my 120 Gallon. If they are Compatible with Yellow Watchman Gobies.