Obi, a baby pygmy hippo, was born three weeks ago. (Photo/Zoos Victoria)
Obi has been learning to swim in the nursery yard, but this was his first time in the main exhibit. (Photo/Zoos Victoria)
Obi's name means "heart" in Igbo, a local Nigerian language. (Photo/Zoos Victoria)
Obi's mom Petre kept a close eye on him in the water. (Photo/Zoos Victoria)
Obi weighed 11 pounds when he was born, but is already up to 28 pounds. (Photo/Zoos Victoria)