Going beyond the distressing notion of the pain inflicted on billions of fish annually, scientists have discovered fish possess many qualities thought only to reside with more evolved species. Culum Brown, Associate Professor, Macquarie University, stated  “In many areas, such as memory, their (fish) cognitive powers match or exceed those of ‘higher’ vertebrates, including non-human primates. Best of all, given the central place memory plays in intelligence and social structures, fish not only recognize individuals but can also keep track of complex social relationships.” (7)

Professor Brown cites the many fish which build nests for rearing young, similar to birds, while others have permanent burrows or preferred hiding spots. He relates the constant challenge for the rock-moving wrasse which have to build a new home each night by collecting rubble from the ocean floor.  This use of tools, which is supposed to belong only to higher order creatures, may be found in other fish who use tools for foraging, rocks for crushing sea urchins, or the archerfish who shoot water to capture insects, to the deep-sea lantern fish which produce fluorescent photophores to capture prey.

Other species of grazing fish display an agricultural inclination where they tend their underwater gardens by constantly removing unwanted algae and encouraging the growth of more preferred species.

Some fish engage in symbiotic relationships to maintain their food supply and/or provide protection. Those who have watched the popular movie “Finding Nemo” will be familiar with the bond between the clown fish and the sea anemone. The clown fish, immune to the anemone’s venom attracts predators who are caught in the venomous entrails of the anemone, which then consumes its prey, leaving some scraps for the clown fish. 

Another species of fish which relies on mutualism to survive is the cleaner wrasse. Its food supply is the dead bits of skin and parasites from the bodies of other fish which the wrasse removes with the utmost care because a careless nip will see the loss of a customer. One way the chastened wrasse will lure back a lost client is through a caressing back rub. Hardly the action of an insensitive and unconscious organism.

Further evidence of the sentient nature of fish has been found in studies conducted to determine whether fish are capable of learning. (8 & 9) Through electric shock and reward stimuli it has been shown fish will stay away from parts of their aquarium where they received an electric shock and taught to respond to stimuli such as sound and light for the reward of food. One study that reduced the reward to only one hour a day found the fish remembered this time and only engaged in the reward-producing behaviour when they knew food was forthcoming.

These examples are just a few of the discoveries that demonstrate fish are feeling, aware and alert creatures.

The aforementioned “Finding Nemo” may have appealed as a sentimental family film but its underlying philosophy of fish sentience is one we need to acknowledge.

Fish may not have many opportunities to ingratiate themselves into human hearts as dogs or cats do but we should be under no illusion that their lack of a voice, a wagging tail or soft coat does not mean they lack the ability to think, feel and act. To quote a line from Ian McEwan’s novel “Saturday”, It is a good thing that sea creatures have no voice, otherwise there’d be howling from those crates.” (10)