It depends on a lot of things...the individual fish, tankmates, aquascaping.
IME with lionfish, giving them ample room to swim improves their mobility. Let's face it...if you live in a phone booth, you're not going to move much because you CAN'T move much.
Also, as mentioned, once the fish know about "the food god", they will be there to greet you whenever they see you, hoping for a tasty treat. This basically means that if they're in an area where they can see you, they will tend to flirt with you...some will even learn to spit water at you to get your attention.
Tankmates also play a part in how mobile lionfish are...if they feel threatened, or are in the company of fast swimmers, they will tend to perch more.
Altho "doable" with a lot of attention to water quality, a 24 gal (I'm assuming it's one of the plug-n-play nano setups) is a bit tight for a fuzzy, IMHO, however, we often keep juvies in tanks that small and move them up when the time comes. If you want a fish you can keep for life in a 24, the fu manchu is a better choice.
A final thought is COVER THE TANK...lionfish, especially fuzzies can jump really well.
HTH