Fish challenge misconceptions


Picture of a fish

A conference of vets in Hobart (Tasmania, Australia) last week heard that fish are smarter than is commonly thought.1

For example, studies have shown that the idea that fish only have a three-second memory is a myth. Veterinarian Dr Richmond Loh says fish were tested by making them use levers to get food. And when the researchers restricted the food to a specific time of day, the fish soon figured out not to bother pushing the levers at other times.

While many might be surprised at such exhibitions of fish intelligence, we have earlier reported that researchers have known for some time that fish aren’t dimwits. There has been a ‘sea change’ among fish biologists in conceptions of the cognitive abilities of fishes:

‘Gone (or at least obsolete) is the image of fish as drudging and dim-witted peabrains, driven largely by “instinct”, with what little behavioural flexibility they possess being severely hampered by an infamous “three-second memory”.’2

Picture of a gold fish


Instead, goldfish memories are now known to last at least three months. And researchers observed that Australian crimson spotted rainbowfish, which learnt to escape from a net in their tank, remembered how they did it 11 months later.3 This is said to be the equivalent of a human recalling a lesson learnt 40 years ago. Fisheries biologist Culum Brown, with research experience at the Universities of Queensland (Australia), Edinburgh (UK) and Canterbury (NZ), made this very telling comment:

‘Fish are more intelligent than they appear. In many areas, such as memory, their cognitive powers match or exceed those of “higher” vertebrates, including non-human primates.’4

The fact that fish intelligence can ‘match or exceed’ that of chimps highlights the fallacy of standard evolutionary misconceptions that the apes, as ‘our closest evolutionary relatives’, would be the animals expected to most closely match the intelligence of humans. Those misconceptions are based on the idea of an evolutionary progression from ‘primitive’ to ‘advanced’. But no such ‘progression’ exists.

Rather, all kinds of animals were created separately, each according to its own kind, including the fish—beautifully designed to occupy their intended habitat (Genesis 1:22).

Man, however, was special. Being made in the image of God, man was told to ‘rule over the fish of the sea’ and the other creatures (Genesis 1:26–28). This perfectly explains why it’s humans who study and write research papers about animals, rather than the other way around!


  1. ABC News Online, Vet dispels goldfish 3-second myth, <http://www.abc.net.au/news/newsitems/200605/s1645894.htm>, 24 May 2006 . Return to text.
  2. Laland, K., Brown, C., and Krause, J., Learning in fishes: from three-second memory to culture, Fish and Fisheries4:199–202, 2003. Return to text.
  3. The research paper reporting this result said it ‘is comparable to the long-term maintenance of hook shyness in carp and salmon for over a year’. Brown, C., Familiarity with the test environment improves escape responses in the crimson spotted rainbowfish, Melanotaenia duboulayi. Animal Cognition4:109–113, 2001. Return to text.
  4. India Daily, Experiments reveal fishes are getting extremely intelligent—will they replace humans as Intelligent beings on the earth?, <http://www.indiadaily.com/editorial/1849.asp>, 25 May 2006 . Return to text.
Published: 29 May 2006

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