Waterhorse Dragons received their name due to their horse-like physique and endearing behavior. They are capable of surviving out of water, and when on land their skin secretes a gelatinous goo to retain moisture. However, their large paddle feet are better suited for swimming, and waterhorse dragons tend to move very awkwardly when on land. Waterhorses are very friendly dragons and enjoy playing with humans.

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.

Aquahippo has very big feet. Very big indeed. So big that they really embarrass him. So although he can walk on land—he just doesn't, except in dire emergencies. He likes to swim along by tourist beaches and give rides to little children who are afraid of the water—he has cured many a swimming phobia by doing this, and is immensely popular; children rush to the water's edge whenever he appears—but always feels bad when he feels he has to refuse to build sandcastles.

He loves ice cream and broccoli—not in combination—and has almost perfect teeth. He broke one on an oyster shell, years ago, and is rather embarrassed about that too.