You could always remove the water, toss in some milkweed, collect a couple of Monarch caterpillars, and before you know it you will have some butterflies. Oh, wait, you wanted marine type. Sorry.
So the correct answer many have already provided is that no, non will really work long term. For health of the aquarist or the fish. One has to factor in the aquarium size, rock work, coral size, substrate, and equipment inside as it all takes up space. Space that will take away swim lanes for fish. Butterflies, for which you didn't mention what ones you are interested in, are usually larger wild collected. There are plenty that are captive bred, raised, that are small but again they grow fast and before you know it Bob is your Uncle and you have to remove it or upgrade. Both new hobbyist say they will, but don't.
The fish in question may not want to leave. Trap? Maybe, maybe not. That doesn't work now you have to use nets and a friend. No friend now you are Squiddly Diddly using both of your arms with nets trying to catch it. Stress on you, stress on the fish, and stress on everything in the tank. F-Bombs aside that doesn't work and now you are breaking up your reef to catch something that should never have been added in the first place. Small or not.
TL; DR - do it right the first time and properly stock. There are plenty of pretty fish that one can place inside a display of that size.
Forktail blenny
Dwarf Angels
Starcki Damsel
Royal Gramma
Cardinals
Neon goby
You get the idea. Plenty to choose from. Just trying to save you some headache and frustration down the road by buying something that isn't really the best choice even if small. Do a search on 40 breeder stock list for some ideas. Just ignore anything with butterfly in it. I would also avoid wrasses but that is my personal opinion. That and clowns. Possum wrasse is nice but they need a healthy pod population...