(Asteroid. Probably a whole lot of space-bats, though not sure what the space-bats feed on...)
Non-shallow water-dwellers who have to transition to atmosphere havw to deal with more pressure difference than there is from atmosphere to vacuum. Though it seems they're (now?) perfectly adapted to the common gaseous biome without too much fuss (maybe their 'air suit' is necessary to keep damp, but their heads are unhelmetedand they seem to be airbreathing.
Makes you wonder about the equivalent of vocalisations made by actual fish in actual water, given gills don't have the same necessity to take in and re-expel the breathing medium as lungs, so don't have the natural capability to work by forcing anything through a larynx - even if it could be made to work well enough with the denser fluid. Water-communication seems to be a mix of snaps (cavitating claws), clicks (pulses from a membrane) and whistles (essential 'humming', perhaps with a retained reservoir of air, the effect again sent into the water via a membrane and maybe a buffer organ of incompressible liquid carefully shaped to focus the effect).
Though we're talking of a racs that might well have adapted (perhaps artificially) over a long pre-films history, I don't know much about their EU origin-story, if they have one. There's also Gunguns (clearly amphibious, on a planet with easy and regular access to dry land - they even like their air-pockets/bubbles in their city, so perhaps they're air-biased amphibians rather than mud-skippers with secondary out-of-water capabilities. Kamino is the interesting one. Seemingly the only "land" is the handy facility(/ies) built for interaction with the galaxy that has been mostly made to forget about them for nefarious reasons. They must be entirely aquatic by nature, yet seem to be able to walk around the complex on their tall, clearly bipedal form thar isn't not meant for swimming, but isn't entirely as you'd expect. Maybe something like Dune's levitation modules strapped to their bodies to support them in air?
The more interesting 'race' is of course the Garbage Squid (by whatever name it's officially known) that finds itself well acclimatised to life within the Death Star compactors (possibly a cousin of one of the Dagobah swamp-creatures, or a parallel evolution of some of the similar concepts).
...so, anyway. Ameripol!