I have an almost 2inch Abn in my mixed African tank n never see him day or night haha. He has a tough crowd to hang with, I might see him once a week if I'm lucky, I usually go digging around for him at wc time to make sure he is still kickin, they r great at hiding just doesn't seem like there would be many places to hide in a 2.5. Is that a submersible filter? Have u looked behind it?