There are many methods, perhaps everybody can contribute different methods such as barbless hooks, DIY fish traps, store bought fish traps etc.

This is one I have used many times when all else fails.

One trick I have used on tangs that refuse to bite at a baited hook or go into a trap:
Cut a piece of plexi or glass to almost the depth of the tank, full height and another smaller one that is also full height. move the rock to one end of the tank and make a partial wall separating 1/3 of the tank without the rock. The smaller one will be up against the mostly wall. Hold them from falling with clips of any type, or big rocks against them and shove into the sand. Feed the fish only in the empty end. When the fish you want to catch is in the empty end, slide the smaller piece finishing the complete divider. Sort of like a transparent pocket door in a transparent wall. Once the fish is trapped in the empty end, just net it out.