this creature's name is a lie because it actually dwells in caves, not marshes. It lives deep underground in mostly pitch blackness and is near blind and can really only see light created by others of its species. The coral-antlers that grow on its head and back have small glowing bulbs near the end that attract potential mates- the more prongs/lights, the more impressive the specimen. In deep underground caves, tunnels of water can extend for miles without air pockets, so this creature also has plenty of means to supply itself with oxygen in and out of the water, including external and internal gills and a set of lungs for when it's on dry land. They also feed mainly on small things such as bugs or crustaceans, the only available food to them down in the caves. Because they are quite a bit bigger than their prey, they have to swim very far distances every day just to keep themselves well fed.