3 Myths about Fish

fish apbc blog
Fish: we’ve underestimated them!
For as long as I can remember, I’ve been told that fish are very basic animals, with a 15 second memory, good for very little but eating with chips or watching in the dentist’s waiting room. How wrong we all were. In the last decade, a great deal of research looking at fish behaviour and welfare has been done. This research has revealed a complicated, emotional animal, very different to the unfeeling, reflexive animal we all presumed the fish was. Let’s look at the evidence.
Myth 1) Fish are not capable of feeling pain.
A multitude of studies carried out in the last decade have shown that fish do feel pain. They can learn to avoid a part of their tank where they receive a mild shock. This clearly illustrates pain perception by fish. Another study showed that morphine changed the behaviour of fish who had previously been exposed to a painful experience. Fish without the morphine showed rocking behaviour and rubbing of the affected area. Fish treated with the morphine behaved normally. If fish did not feel pain, they would not have the required systems to process a pain killer. Scientists feel that this is evidence of pain perception in fish. Some scientists do still believe that fish are incapable of pain perception. They state that fish are lacking a key part of the brain involved in pain perception, the neo-cortex. If we buy into this theory, no animals other than humans and higher primates can perceive pain. Tell that to my dog when I accidently step on his paw!     
Myth 2) Fish have 15 second memories.
Imagine an animal with nothing more than a 15 second memory. The animal would not remember the best places for food, where to hide from predators or who to mate with! Fish live in very complex, changeable environments in the wild. Naturally, an ability to learn about the environment (and remember what you learnt) increases a fish’s chance of survival. Many studies have shown learning and memory in fish. For example, fish can remember where they have already foraged for food so they don’t waste time looking there again. They can remember where they have had negative experiences like receiving a shock and remember not to go back to the same place again. They can even remember to perform certain behaviours for a food reward e.g. farmed fish can be trained to swim to a certain location in their tank when they hear a particular noise. They learn within a few weeks to get there quickly to receive a food reward. I think most people with fish are aware that their pets can learn. When I kept fish, as soon as I opened the lid of their tank, the fish swam to the surface, knowing they were about to be fed!
Myth 3) Fish are robots, their behaviour patterns are fixed.
It has long been assumed that fish are not capable of making decisions. All of their behaviour was said to be reflexive i.e. they would always respond the same way to a given situation. This has also been disproved recently. Fish can be trained to feed in a certain part of their tank. If subsequently, this part of the tank also delivers an unpleasant experience e.g. a shock, the fish will avoid the area to avoid the shock. However, the hungrier the fish is, the more likely it is to enter the area of the tank, despite the pain. This shows that the fish is able to make a decision to experience the shock in order to feed. If the fish’s response to the shock was simply a reflex, it would not enter this area of the tank at all, regardless of hunger levels.
So why, despite all this scientific evidence, do we still not feel much for fish? Is it because they aren’t fluffy and cuddly like our cats and dogs? Is it because communication with fish is difficult? Is it because more of us eat them than keep them as pets? Whatever the reason, we all need to give more consideration to these underestimated animals. With new work suggesting that even prawns and crabs can experience pain, we all need to think about how our treatment of animals impacts on their welfare.
Dr. Sarah Millsopp Ph.D. B.Sc. (Hons) P.G. Dip (Provisional Member of the APBC)