Here is a really silly thing to try...
On one of my attempts to catch a damsel, I placed a piece of clear plexi between the rocks and the front of the tank with the top of the sheet of plexi above the water line. Then I lowered a large hand mirror into the tank and propped it against the side of the tank at the far end of the "squeeze shoot". My intent was to lure the aggressive fellow into the shoot by having him see his reflection and think it was another damsel.
Well, the damsel didn't take the bait, but my decorated goby sat in front of the mirror for 2 hours until I finally took the "squeeze shoot" out.
Silly, but who knows, the hawkfish might be vain enough to sit and look at himself.
You know you are a true fish-o-holic if you can field strip any powerhead on the market.