Thanks!
I had to hide the water in the tank because it interfered with the light and reflections.
Let's assume it's clear because it's being cleaned regularly.
Sometimes you have to get creative with being creative ...
As if someone would have heard of fish and them having something to do with water anyway! Fakenews! I think anybody needing water is a very overrated opinion. Thinking of it ... did you know they actually PEE in it? Gross!
Jokes aside, hiding the water is a legit way of circumventing problems with a render. You could have possibly done a bit manipulation with the "glass-texture", to get a little bit more "water-y" outcome.