Deep Sea Dragons, as their name suggests, spend most of their time in the darkest depths of the sea. They have a bioluminescent dorsal spine that serves to attract prey and communicate with their own kind. As with many deep sea animals, they generally eat whatever they can manage to bait. They rarely leave the ocean floor, surfacing only during breeding season. When they do choose to travel to the shallower depths, they avoid bright lights and will only come up far away from shore.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

It can and will always be said that it's Pondfin's fault Aquatail is here. Nii-Chan has reservations whens it comes to collecting doubles of any species, at least for now. Nevertheless, Aquatail is exactly the companion Pondfin has been longing for, and only he can drag her out of any stormy depressions she happens to fall into. However, unlike his female counterpart, he will never try to venture anywhere less than 100 meters below sea level. This means Pondfin is the only one of the pair you are likely to see, and it also means Pondfin is frequently confined to the dark depths of the ocean. The two deep sea dragons can often be seen twining around each other, if one can dive deep enough to see them.