Once they ate all my fish, I stopped feeding the tank. They started to move around in search of food (I assume). I would remove them when they were moving (not well attached) or if they got onto a small rock that could be removed. My tank was fishless for about 4 months last year. Or so I thought. Turns out there was still a watchman goby living towards the back with his pistol shrimp buddy. I guess they lived off the pods...which there was a ton of. My glass was alive with "bugs" during that time.