Is it true that fish only have a memory of a few seconds? I'm house sitting for my sister and am looking after her fish and they seem to know exactly when its feeding time and where they are going to get fed?
Fish have exceptionally good memories, although it can depend on the species.
Carp for example are highly intelligent and can often learn to do minor tricks. They recognise their owners and can associate certain objects with either food or danger.
If fish only had a few seconds of memory, they'd keep forgetting to breathe !!!
Yep...there is a small wooden box that you hang from a pergola over your koi pond. The box is in a Japanese style but you fill it with fish pellets.
A string runs down to the pond a a small "ball" is on the other end.
The koi will quickly learn that if they pull this string, they will get a small amount of food from the gods above.