I have a lot of rock work so I bought a really nice acrylic fish trap off ebay. Seemed like I could catch any fish I wanted but not that damsel. Those buggers are SMART. I tried pellet, flake, clam, daphnia. When nothing was working I trapped every fish that went in and put them in the sump so they would not disrupt my fishing process. The instant I put mysis in the trap my cleaner ran in, then the damsel went into it right away. I never thought the food would have mattered, but they are very partial to mysis apparently.