FACT: Complex personalities of fishes

Fish appear to be individuals with complex personalities, according to new research. Researchers tested the idea that Trinidadian guppies all had a fairly standard response to potential dangers. The theory went that they had a “simple spectrum” of reactions to danger – some things were more frightening than others but the fish basically all responded in the same way.

However, when confronted by a new situation or a potential predator, such as a model of a heron in laboratory tests, the guppies proved they were all individuals. Some were, essentially, braver than others.

One of the researchers, Dr Tom Houslay, of Exeter University, said: “The idea of a simple spectrum is often put forward to explain the behaviour of individuals in species such as the Trinidadian guppy. “For example, when placed into an unfamiliar environment, we found guppies have various strategies for coping with this stressful situation – many attempts to hide, others try to escape, some explore cautiously, and so on.