Protestors wrapped in fishing nets lay prostrate in front of Ripley's Aquarium on Saturday afternoon, while others carried signs reading messages like "abolish fishing" and "animals are not ours to use."
Around two dozen activists took part in the demonstration to protest both hunting marine animals, and having them in captivity at aquariums.
"Hundreds of billions of marine animals are murdered every year when we don't need to consume a single fish, or lobster, or any animal," said protestor Len Goldberg.
"A lot of people are under the impression that aquatic animals don't feel any pain, which is obviously untrue," echoed protestor Adam Stirr.
Goldberg said Ripley's Aquarium, the popular tourist spot near the CN Tower, was a specific choice because marine animals don't belong in "basically a bathtub."
It's not the first time the public aquarium has come under fire, with previous protests and controversy surrounding the facility's captive aquatic animals, including sharks.
On its website, the aquarium says it is "dedicated to the health and safety" of the animals.
"From daily care to research and conservation initiatives, Ripley's Aquarium of Canada strictly adheres to the utmost standards of animal welfare and security," the website reads.