This seems like a perfectly reasonable question to ask, because that is what they are supposed to do, aren’t they? The simple answer is yes. And no. As discussed above, fish can be annoyingly indecisive (or decisive depending how you look at it). One type of saltwater aquarium fish trap can work amazingly well for one fish, but the same trap could be completely avoided by all other fish.
Unfortunately it may come down to trial and error. By way of easing the lack of success, I am going to suggest what I would do based on the knowledge that I have accumulated over the years. Hopefully you won’t be asking, ‘How do you trap saltwater fish?’, for much longer.
I would look at their behaviour to determine how likely they are to venture into a trap. If they are the type of fish that is always on the hunt, like a Wrasse, or holds back from the feeding frenzy, I would try a trap with a sliding door.
If they are the type of fish that readily comes to the front to feed, either to be fed by hand or to pick at food stuck to the glass, I would suggest a floating trap.
I bet you must be guessing by now that it is not always that simple, and you would be right. We all have some fish that are skittish and hold back. Mine is a Yellow Tang that will go nowhere near anything new in the tank. If my intention was to catch my Yellow Tang I think I would need to begin by luring it over to the trap over a few weeks by placing all food in the trap.