[9] The aquarium contains 1,500 species, including fish, marine mammals, birds, snakes, amphibians, and insects.

As one of the first inland aquariums in the world, the Shedd had to rely on a custom-made railroad car, the Nautilus, for the transport of fish and seawater.

In 1930, 20 railroad tank cars made eight round trips between Key West and Chicago to transport 1 million US gallons (3,800,000 L) of seawater for the Shedd's saltwater exhibits.

The Aquarium was located immediately north of the fairgrounds, and the museum gained exposure to a large international crowd.

The central aquarium building is octagonal, fronted by Doric columns and a formal staircase and topped by a dome.

Aquatic motifs are worked in at every opportunity; tortoise shells, dolphins, octopuses, waves, and even the Trident of Poseidon can be found all over the aquarium's exterior and interior.

[17] The Oceanarium is done in a more modern style representing the Pacific Northwest, but one that blends with the older part of the building.

The oldest galleries in the aquarium feature exhibits on oceans, rivers, islands and lakes, and Chicago's own local waters.

Species from this area on exhibit include a green anaconda, red-bellied piranhas, electric eels, freshwater stingrays, dwarf caimans, caiman lizards, wattled jacanas, yellow-spotted river turtles, red-footed tortoises, yellow-footed tortoises, mata matas, Arapaimas, different species of South American birds, fish, and frogs, and many more.

In 2003, Shedd opened Wild Reef, a permanent exhibit located two levels below the main building.

The exhibit contains a total of 525,000 US gallons (1,990,000 L) and recreates a Philippine coral reef on the Apo Island marine reserve, complete with living coral, multiple species of fish and rays, and a collection of sharks such as sandbar, zebra, blacktip reef sharks, white-spotted guitarfish, Spotted wobbegongs, and Japanese wobbegongs.

The main draw of this attraction is a 400,000-US-gallon (1,500,000 L) shark tank with 12-foot (3.7 m) high curved windows, allowing visitors a diver's-eye view.

The Wild Reef exhibit also features a saltwater tank display area where coral is propagated and grown for conservation purposes.

Several of the sea otters that lived in the aquarium in the past were rescued from the Exxon Valdez oil spill in 1989.

Films shown have included SpongeBob SquarePants 4-D, Ice Age: Dawn of the Dinosaurs, and The Polar Express (seasonal).

[23] This exhibit opened on May 25, 2018, and focused on the visual beauty of sea life, with sections called "Color", "Patterns", and "Rhythms."

[29][30] Granddad Walter Chute, the aquarium's director from 1928 to 1964, wanted rare fish to attract the 10 million tourists expected to visit Chicago for the exposition in 1933.

Granddad, an Australian lungfish, arrived at the Shedd in 1933, along with his mate, from Sydney during the Century of Progress world exposition.

The Shedd Aquarium currently has eight living Belugas as of November 15, 2022: Naya (F), Beethoven (M), Kayavak (F), Bella (F), Aurek (M), Kimalu (F), Annik (M) and Atlas (M).

[33] On July 3, 2019, Mauyak gave birth to a male calf, Annik, bringing the total number of belugas at Shedd to eight.

Trainers fed Kayavak fish, cared for her day and night, taught her how to "be a whale", and she thrived to be the healthy adult she is today.

Puiji died on Wednesday, October 26, 2011, following a seizure after having been undergoing treatment for an undisclosed medical condition over the course of several months.

[41] Unfortunately, because the calves were premature twins, the first calf had multiple health issues and died 15 days later despite being in the care of staff members.

[42] Yaku (son of Kenai) was euthanized on February 26, 2022, due to failing health brought on by a tumor in his chest.

[43] Kenai (Exxon Valdez oil spill survivor) was euthanized on October 9, 2012, due to failing health brought on by advancing years.

[44] Kachemak (oldest sea otter in a North American Aquarium/Zoo) was euthanized on August 24, 2013, due to failing health related to age.

The aquarium has seven white sided dolphins: Loke (F), Kri (F), Katrl (F), Munchkin (F), Makoa (M), Elelo (M), and Harmony (F).

Piquet was moved to Miami Seaquarium in early 2018 for a breeding loan and Ipo was transferred to Shedd to take her place.

She was transferred to the Mystic Aquarium in 2009 due to construction on Shedd's oceanarium, and the Miami Seaquarium in 2013 for a breeding loan.

[52] The move was a result of several USDA reports that noted Miami Seaquarium's poor facility state.