Further proof (if required)
I've never seen one buy a lottery ticket either.
Smug humans tend to think fish are the stupidest of all beasties. But that belief has turned out to be a load of barnacles after boffins revealed the true intellect of our fishy friends. Researchers from the University of Bath joined forces with London's Queen Mary University to work out how zebrafish perceive their deep sea …
After stalking fish stalking me around reefs in tropical waters in my well spent spear fishing youth I was amazed how hard it could be to fool some of the fish, some of the time. Bit like humans really...
A beer for the restraint in fish puns to editor and author. Note for the soft of heart, some of those fish had big teeth and were over 2 meters long. One was closer to 4 and tried to bite.
... in a tank opposite the telly --- they would get fed when the evening's telly was over. When the telly went off, up they all came to the surface; I swear some of them even learned to recognize the tell tale signs of the cast-list going up before I even hit the off button.
Even C. a. auratus are certainly a long way from the "Holy Carp! When did I get a castle?" stereotype.
Apparently even amoebae can learn to associate correlated stimuli. That's pretty good going for a monocellular organism without anything we can recognise as a nervous system.
Can any fish scale the heights that "mere" invertebrates have managed? Last night on TV, watched an octopus gather up two half coconut shells, put one on each side of itself, and pull them together to make a secure home. Found tool use, using unnatural entities dropped by human beings from above. We've not been chopping coconuts in half with machetes for very long, so it can't be instinctive ... and octopuses have only a couple of years of life in which to learn anything.
Perhaps, though, it's an unfair comparison. If an octopus is the most advanced mollusc, then shouldn't a human be seen as the most advanced fish (ie, vertebrate).
and adaptation is unlikely
Although I did read about an octopus being kept in a marine biology lab, that handled brief spells in air rather well. The lab had a problem with fish disappearing from a tank. They rigged up a camera to catch the thief. The next night they watched their octopus lift the lid off its tank, walk across the lab to the fish tank, catch a fish, walk back to its tank, and pull the lid back over itself from the inside.
Molluscs have, of course, successfully colonised the land. (Slugs. Yeuch! ) Fortunately for us, no long-lived intelligent ones with tentacles. Not yet. Give them another fifty million years ....
If they could live for longer and travel on land, or worse, in the air, then they might indeed supersede humanity. There is in fact already one intelligent octopus-like Being with tentacles, or Noodly Appendages, as they are known among his priests. Fortunately, it is benevolent to us lesser mortals.
There seems to be some evidence that a few species of fish have limited tool use, they also think they may have found play behaviour in some fish. If you have ever dived a reef that has Titan triggerfish on them they can be pretty darn sneaky in doing things like distracting divers whilst another sneaks in for attack.
I don't know why we assume fish and other species have less mental processing ability.
Visual acuity is surely the absolute overriding method of self preservation from predators, particularly for fish, and therefore evolutionary pressure would obviously mean that fish nowadays are very good at it.
This is not, however, what I would call a convincing yard stick for measuring "intelligence", which to me is more about abstract thought.
... have known that fish aren't as stupid as is commonly believed. The 7 second memory thing in goldfish is bollocks, too.
When I kept them in the past, at first they'd always be timid and hide behind the ornaments whenever I disturbed the water. But as time went on, they'd recognize the blue tub of goldfish flakes and go crazy whenever I picked it up and held it near the tank. I even had a few that would eat the food from my hand when I held it at the top of the water.
A friend of mine used to have a large fish pond in his garden. He used to put half submerged pastic bottles in it (to protect against freezing in the winter), then couldn't be bothered to take them out again. During the summer months the fish started to nudge them about the pond, sometimes two or three cooperating.
Demonstrating the importance of using scientific names. Yes, Danio rerio is freshwater (Himalayan), and so is Percina kathae (North American), but Pterois volitans (Australian) is marine - though coral reef, not deep sea. So which was it, and did Dr Proulx et al really do the experiment deep-sea?