They are in separate systems and solitary. The orange fellow is about an inch and a half long, the brown guy is about two inches. I actually bought two orange Antennatus; they were caught together, supposedly a pair. One didn't make the shipping process.
Froggies from Genus Antennatus don't really make nice show animals. They are very cryptic and reclusive.
I have had good results keeping other frogfishes together but they need to be the same size and species group, closely observed ... and regularly fed. Don't recommend it for most people.
I tracked down a copy of
Frogfishes of the World , by Pietsch and Grobecker ... bought it as a birthday present for myself ... yay! Unfortunately had to spend a bundle on it
... but worth it.