Far from being instinct-driven dunces, held back by a three-second memory, fish were cunning, manipulative, cultured and socially aware.
In some respects of their intelligence, they could even be favourably compared with non-human primates, it was claimed.
The three scientists from the universities of Edinburgh and St Andrew’s in Scotland, and the University of Leeds, said conceptions of the psychological and mental abilities of fish had undergone a “sea change” in the past few years.
Biologists Calum Brown, Keven Laland and Jens Krause wrote in the journal Fish and Fisheries: “Gone (or at least obsolete) is the image of fish as drudging and dim-witted pea-brains, driven largely by ‘instinct’,’ with what little behavioural flexibility they possess being severely hampered by an infamous ‘three-second memory’.”
Recent research had shown that fish not only recognised individual “shoal mates” but monitored the social prestige of others, and tracked relationships. They had also been observed using tools, building complex nests and exhibiting impressive long-term memories.