This season on Working, we took a trip to Baltimore to chat with some of the city’s residents about how they make a living there. We’re hoping to learn a little about the ways Baltimore shapes their work—and the ways they’re shaping Baltimore by working.

Listen to this episode of Working with special guest Leigh Clayton:

For this episode, which you can listen to via the player above, we spoke with Leigh Clayton, director of animal health and welfare at the National Aquarium. She and her team are responsible for the care of something like 800 distinct species—close to 15,000 animals in all. Though that’s a huge range, learning their peculiarities isn’t necessarily that difficult. All veterinarians, Clayton says, have to be adaptable, taking “facts you know and approaches you know from one species and apply it to similar species.”

Diagnosing a sick fish, she says, also isn’t all that different from diagnosing any other animal: As she explains, “We often are looking for changes in their behavior and changes in how they look.” A fish that’s ill may fall behind the others in its school or hold its fins differently than it otherwise would, for example. In other circumstances, they sometimes change color, much as you or I might go pale when we get hit by stomach bugs. Even the diagnostic tools—X-rays, ultrasounds, and so on—are similar to those that physicians use to test more familiar terrestrial mammals.

Clayton tells us that one of the things that surprises visitors most is that you actually can take a fish out of water to perform surgery on it. In this episode, she goes into that and more, even sharing a story about a particularly memorable thyroid surgery on a gecko. She also talks about the shape of a typical day and leads us through what happens in an emergency. And, of course, she goes into the aquarium’s relationship with the nearby Chesapeake Bay, including the institution’s involvement with local animal rescue groups when wild animals in the region are in crisis.

For Clayton, the aquarium’s facilities—and their links to the surrounding environment—offer educational opportunities as well. “There’s a lot of fish out there. It’s fun to point [them] out,” she says of the harbor that abuts the aquarium. “People have no idea.”

Then, in a Slate Plus extra, she shares some thoughts about what it’s like to work with octopuses—strikingly complex, and often individually eccentric, animals. If you’re a member, enjoy bonus segments and interview transcripts from Working, plus other great podcast exclusives. Start your two-week free trial at slate.com/workingplus.