@ 0:19 No I don't know, what does he mean by "they have a good relationship" Do the fish do something for the swan that I can't see?

#2 Yes, but you don't have your eyes enough open to see it. It makes feel the swan very good and useful.

The swans are feeding themselves. They're using the water to make the food go down more easily, and the fish are there to get whatever falls out of their bills.

Oh my god....#3 "It makes feel the swan very good and useful." What drivel.

#4 Thank goodness for the simple common sense explanation. Common sense isn't very common anymore.

#4 Absolutely Wrong! A friend of mine runs a koi farm in Indonesia and employs a flock of Black mute swans to feed the one's in the middle of the lake. The black Swan is known for it's fish feeding skills all over the world. The cormorant (a relative of the black swan) is used by Indonesian fishermen to feed fish on wild rivers (you may have seen them on adverts)Unfortunately the method adopted by the Cormorant involves the bird bringing the fish back to the boat for the fishermen to feed, at which stage the fisherman simply keep the fish.

#4 totally true.

#5 "Common sense" is used to express things that most people know on a regular daily basis in the society they grow up, not that ducks shake the food in water to rinse it off. That there was a explanation other than the title insinuated should be of course taken in consideration, and it would be reasonable to search for that alternative. But i would not call it common sense to know that ducks shake food in water like that and that the fish around come and eat the waste on a daily basis.

#8 I was targeting #3's assertion that the swans were doing it because it makes them "feel" very good and useful.
That is why I quoted his quote.(but ignored his bad grammar)
I guess you go along with that sentiment about swans being benevolent to fish?

Are there any movies of white swans doing this?

Gaping mouths of baby birds trigger a feeding instinct in parents.
The gaping mouths of the fish trigger this same instinct and the swans react, putting food into their mouths.
The fish will have become used to being fed on the surface and won't care who does the feeding, the humans or the swans.

Ohhhhhhhh #5 !! Je vais désormais écrire dans ma langue, et ne plus faire l'effort d'écrire dans une langue où tu considères que mon niveau est moindre. J'aimerais bien que tu puisses parler une autre langue de la même manière. Bisou

Faith in Swanity has been restored..

The suggestion that the swans are enjoying feeding the fish is not as preposterous as it might seem.

We know that birds and animals have reward circuits in their brains, so when they follow through and respond to stimuli they are 'rewarded' by these circuits in their brains.

Lacking the cognitive ability to know that without feeding them their young will die, evolution solves that problem with instincts triggered by gaping mouths, and rewarding the fulfilling of that desire by stimulating the pleasure centres in the brain of the parents. Without this reward system the parents wouldn't go through the hardships involved in bring up their young.

Humans are activating these same pleasure centres, which evolved for the same reasons in us, by eating foods and use of drugs.