You might be able to get away with housing an angler all alone in a 24g nano cube, but it probably is not a good idea.
Besides the point of the angler in a smaller system, I would not host a mantis with any fish, or an angler with any crustacean.
Do a single peacock mantis. (my favorite of the crustaceans)
3' fine sand bed 1x Orange Stripe Prawn shrimp goby, 1x sixline wrassemated pair of true percula clowns, 1x CBS shrimp, 2x peppermint shrimp, 1x pistol shrimp, 1x tiger tale cuke
, ~20+ snails, ~10+ hermits, 1xserpent star.
green Bubble coral, hammer coral (8 heads!) ,various Zoos,green finger leather, green star polpys ,shrooms
175w 10k MH
28w actinic 03
2x maxi jett 1200
Prizm skimmer (modded)
Hagen powerfilter(for running carbon 24/7)
nano arctica chiller