public aquariums


There are over 200 public aquariums worldwide that exhibit many species of animals. The majority of animals in public aquariums are fin fishes, with the next largest group of animals held captive being invertebrates, which include crustaceans, cephalopods, like octopuses and squids, jellyfishes, sponges, and mollusks.

Living in an Aquarium

Public aquariums often house many species of animals together. This makes it difficult to ensure that each species of animal has the proper water temperature, salinity, pH, dissolved oxygen, and pressure.

Like animals held in zoos, aquatic animals held in captivity suffer from diseases and physical injuries from the conditions they are held in or fighting with other animals. One study found evidence of possible physical health problems in 74% of animals in aquariums. Many of the health problems seem to be caused by husbandry techniques, like the mixing of species in an exhibit, feeding methods, the regulation of the water chemistry, or the interactions with visitors. Animals held in aquariums also suffer mentally from their conditions, they exhibit boredom, frustration, and aggression. Pacing, circling, spiraling, head bobbing and other abnormal behaviors, which are all indicators of stress, have been observed in animals in 90% of aquariums.

Dying in an Aquarium

Mortality numbers are not publicly available, and there is no acceptable standard mortality rate for the industry. Here are a few examples of what it’s like to die in an aquarium from recent news articles:

  • More than a third of all animals at The UK’s Sea Life aquarium (812 out of 2,293 animals) died in 2018.
  • In 2015 and 2016, across the eight Sea Life Aquariums in England, 4,500 animals including sharks, rays, and jellyfishes died.
  • At the largest public aquarium in Europe, 30 hammerhead sharks died in 8 years from fungal infections.
  • More than 10% of the sharks in Dubai Aquarium, the world’s biggest aquarium, have been killed in attacks. Sand tiger sharks have killed at least 40 smaller reef sharks and been aggressive towards divers working in their tank.
  • In Tokyo in 2017, 1,235 fishes, which were 94% of the fishes in one of its tanks, died due to lack of oxygen, after they turned off a bubble-generating tank cleaner​​.
  • In 2013, more than 200 marine animals died at the Portland Aquarium according to a death-log obtained by The Oregonian. Among the casualties were bamboo sharks, sea horses, garden eels, sea stars, crabs and dozens of fishes. They died from starvation, infection, high temperatures, being attacked by other animals, being caught in drains and screens, power outages, being crushed, stress, parasites, and jumping out of the tank.

Why do we have aquariums?

For conservation? One study found that 98% of animals held in public aquariums are not endangered or threatened, and 99.9% are not part of a captive-breeding program (if you even consider captive breeding to be legitimate conservation, as animals are usually not released into the wild). Many fish species held in aquariums cannot even be bred in captivity. It is estimated that the majority of animals, 79-89%, held in aquariums are taken from the wild, which is the opposite of conservation.

To learn more about these animals? Studying animals who are held captive in small tanks that in no way resemble their natural environments, and who are trained to behave in ways that they would not in the wild, does not provide any insight into their natural biology, behavior, or ecological role. Scientific research involving captive aquatic animals has done little to advance scientists’ understanding of wild animals.

Education of the public? Most surveys have shown that the overwhelming majority of patrons of aquatic animal parks go to be entertained, not educated. A study showed 83% of attendees don’t read signs (and many times signs include inaccurate information). A study of over 2,800 children surveyed them following visits to London Zoo on conservation biology-related learning. They found the majority demonstrated no positive learning outcomes at all. Indeed, many children were deemed to show not just a lack of learning, but a negative learning outcome. The type of education that is provided is miseducation, that capture and captivity is ethically acceptable.


An Investigation Into theUK’s Largest Public Aquarium Chain by Captive Animals’ Protection Society (2014).

Evaluating Children’s Conservation Biology Learning at the Zoo by Eric Jensen, Conservation Biology (2014).