A second pup was born on Monday, a spokesperson said. No photos or videos of that pup were immediately available.
In a statement, the aquarium said the two pups "are achieving every milestone they should be achieving together at this point, such as nursing, grooming, bonding, and recognition vocalizing."
The not-yet-named pups are "quite curious" and have begun to explore their habitat, the aquarium said. They have also started teething and playing with their toys.
This week, staffers will introduce the pups to a small amount of water so "they can become proficient at learning how to close their nostrils and hold their breath…an important first step in learning to swim," the aquarium said.