At first, the 3-week-old hippopotamus, Obi, seemed to stick close to his mother in a video from the zoo, before playfully ducking underwater to explore his new surroundings, then scrambling back up for air.
Obi had been practicing in the nursery yard pool, but Thursday's plunge marked his first swim in the bigger, exhibit pool, according to the zoo.
"He loves the water and spends hours in the small pool, so he is ready for the next step," said Obi's keeper, Justin Valentine, the zoo's wild sea manager, in a news release from the zoo.
"He's only little so about 10 to 15 minutes and he's a bit tired and he has to take a break," Valentine added in a BBC News video. "And then he's back into it right away."
According to BBC, Obi broke the 33-year dry spell at the zoo during which no pygmy hippos were born. His species is classified as endangered in the wild, which the zoo says makes Obi’s success that much more exciting.
Obi has been gaining up to half a kilogram (about one pound) a day and now weighs more than 13 kilograms (about 29 pounds), compared to his 5-kilogram (about 11-pound) birth weight, according to the zoo. Typically, adult pygmies will grow to about two-and-a-half feet tall and about 550 pounds, which is about a quarter the size of a normal hippopotamus, the BBC reported.