You fill the bottle with half of the water, you put the fish in, you can fill in the other half. If you start with the first half, you will end up with more water.
Yes, there are bad metaphors, and people who take metaphors too seriously. That you can conjure a bad metaphor with somewhat similar to semantics to some other metaphor does not mean that said metaphor is bad.
That water overflow step is missing / implicit. But that's an observable event.
then you fill 3 liter bottle again, and pour the contents into the 5 liter bottle until the 5 liter one is full
empty the 5 liter bottle, and pour the 1 liter in the 3 liter bottle into the 5 liter bottle
fill the 3 liter bottle again and pour that into the 1 liter already in the 5 liter bottle to get 4 liters of water
> Given a 3-liter container and a 5-liter container, both initially empty, and access to tap water, how can you measure exactly 4 liters of water without using any additional containers
I've offered and received some convoluted metaphors recently, love leaning hard into this one.
Not sure, I used to be better at diagnosing this type of episode.