Minecraft water and animals?

I have two questions:

1: At Minecraft, I'm currently building a zoo and have already completed some enclosures and pools. I notice very often that e.g. All fish or all mules within their enclosure always try to stand in the same place, which looks very strange, they should just swim around - or run like any normal animal, that annoys me a lot… Maybe someone knows why and how can you get that away?

2: I often watch YouTube construction tutorials and I often notice (e.g. At LarsLP) that his water looks very different from mine. With me there are so tiny little squares (since MC is all square). With him, however, the water looks totally real, his colors are generally much more brilliant than mine and he has shadows that I don't have. Could that be because I have the Windows 10 version and maybe the Java version (which I don't know exactly)?

Oh! And as an explanation, I wanted to take a screenshot and post the photo here. On the internet it is said that with F2 / F1 you take a screenshot and nothing happens to me, so here is my third question: How else can you take a screenshot?

Lars probably uses a texture pack that makes it look like this. And that with the animals, I don't know

For me, the animals very often all hang around in one place. Don't know why either.

So that his water is so real that it is very likely that he is playing with shaders:

Because of the screenshot you have to press ctrl + shift + 3. On Mac you have to use cmd instead of ctrl. If it still doesn't work, you should have a program called snipping tool. It also works

Question: You can't change that.
Question: He uses a shader. You should actually be able to download a shader too. Unfortunately I don't know.