If you’ve ever gasped at a shark gliding through the National Aquarium’s Blacktip Reef exhibit or paused to watch fish dart through the floating wetlands in the Inner Harbor, your life has been touched by the work of Jack Cover.

Cover, who died after a brief illness at age 69 on Jan. 7, had a hand in shaping nearly every major exhibit at the aquarium during his 37-year tenure.

“Jack had an incredible wealth of knowledge, not just about the aquarium, the animals, the exhibits, our guests, but also about the Chesapeake Bay watershed and the animals that call it home,” said Jennifer Driban, the aquarium’s interim CEO and president.

Mr. Trash Wheel, the Waterfront Partnership’s anthropomorphic garbage strainer, posted a tribute to Cover, calling him “a great friend and steadfast steward of the harbor.”

Cover once fished a 5-foot-long ball python out of the trash wheel with his bare hands, an event Peabody Heights brewery memorialized with its Mr. Trash Wheel’s Lost Python Ale.

“Whether you were human, reptile, invertebrate, or a sentient trash interceptor, Jack showed up,” Mr. Trash Wheel’s post read. “That’s just the kind of friend he was.”

Cover’s love of animals began with a chance encounter with another snake.

A school bus driver seized a ringneck snake from an unruly passenger in the early 1960s, knocked on the door of the Cover family’s Hampden home and asked if Jack and his siblings would care for it.

Jack, who was around 6 or 7, was immediately smitten by the creature, he recounted in a tribute the aquarium published at his retirement in 2024.

“I probably stared at it for an hour,” Cover said. “From there I started checking out books about reptiles from the Enoch Pratt Library. It just became something I was obsessed with.”

Although Cover’s parents did not share his love of reptiles, they encouraged his interests and allowed him to keep snakes and a 5-foot-long speckled caiman in the basement.

Cover spent his formative years searching for snakes in Wyman Park, riding his bike to the Maryland Zoo to chat with the head of the reptile house and joining the herpetology club at Baltimore Polytechnic Institute.

He graduated from what was then called Towson State University in 1978 with a bachelor’s degree in biology and a focus in herpetology. He spent years working in a lab that extracted venom from king cobras, scorpions and black widow spiders before moving to Texas, where he worked for five years as a herpetologist at the Fort Worth Zoo.

He had long wanted to work at the National Aquarium and was happy to move back to Maryland when a herpetologist position opened in the Upland Tropical Rain Forest.

The job allowed Cover to devote himself to his passion for animals and biodiversity — and shape the future of the aquarium.

After hearing reports in the 1980s that blue poison dart frogs were extinct in their native habitat, Cover traveled to Suriname, where he discovered the endangered amphibians in the wild. The aquarium later became the first institution in this country to hatch and care for the frogs.

Cover also traveled to Australia, Costa Rica, Panama and Venezuela to research habitats for aquarium exhibits.

Glenn Page, who served as the aquarium’s director of conservation from 1996 to 2006, recalled camping in Costa Rica with Cover and other staff members. Cover found a highly venomous coral snake late one night, popping it in a “flimsy” pillowcase to show the rest of the group in the morning, Page said.

Page, who was bunking with Cover, asked him not to keep the snake in their tent.

“Jack mumbles under his breath, ‘What if I double bag it?’ and then put this writhing death adder into his backpack,” Page recalled.

The next morning, the team admired the snake and Cover returned it, unharmed, to the spot where he had found it.

The story is emblematic of Cover’s spirit, Page said. He had a deep reverence for animals, a passion for teaching others about them and a pragmatic and creative manner.

“Jack was able to weave his passion for biodiversity into the grander mission of the aquarium,” Page said. “He was so excited to share information with the wider community.”

Cover brought his love of animals to an even larger audience by appearing with lizards, frogs, snakes and other creatures on “Late Night With David Letterman” in the 1980s.

“What’s in the shark tank?” Letterman asked in one segment as Cover described the aquarium.

“Sharks,” Cover replied. “And fish that try to get away from them.”

This folksy approach and a deep understanding of animals and their habitats powered Cover as he worked on some of the aquarium’s biggest exhibits, including “The Amazon River Forest,” “Australia: Wild Extremes” and “The Living Seashore.”

Cover always looked for opportunities to extend his work beyond the aquarium’s walls, collaborating on programs to restore wetlands at Fort McHenry and Masonville Cove.

Despite his seniority and expertise, Cover would often volunteer to help with bio blitzes and other community events. “He would get there early, help set up and be there all day,” Driban said. “He loved to show people snapping turtles and fish.”

Cover, who became the aquarium’s curator in 2004, successfully lobbied state lawmakers in the early 2000s to outlaw the commercial harvesting of diamondback terrapins, which he considered one of his life’s great accomplishments.

Musician Shodekeh, who curated the aquarium’s first Voyages arts collaboration event in 2022, recalled that Cover was eager to show him the wonders of the exhibits.

“Whenever I saw him, he would stop and talk and make space for me to ask questions,” Shodekeh said. “He was gentle in the way he moved through his work and the way he interacted with people.”

One of Cover’s greatest triumphs was one of his final projects at the aquarium, the creation of the floating wetlands, which opened in 2024.

Charmaine Dahlenburg, the aquarium’s director of field conservation, said the ambitious and unique project took 14 years to complete.

Although it wasn’t under Cover’s purview, he jumped into the project and began to strategize how to keep the water flowing. After talking through a design with colleagues, Cover headed to Michael’s craft store, bought a block of Styrofoam and carved it into a prototype of an airlift, Dahlenburg recalled.

“He had such a clear vision in his head of what was going to work,” she said. “No one but Jack had that Jack knowledge.”

In addition to coming up with the design and concept, Cover did much manual work on the wetlands, transporting oyster shells and other materials to create habitats.

As the exhibit was about to open, Driban recalled, Cover, standing in knee-deep water, exultantly lifted a creature he was delighted to encounter there: a diamondback terrapin.

Cover is survived by his wife, Carole; son, Zak; and the many projects he helped bring to fruition.