submarine for pangasius-fishfarm

....here we have an artificial fish: in our project of fish farming
https://grabcad.com/library/farm-for-pangasius-and-ducks-1
we have a situation where very, very many pangasius - up to 400,000 fish - swim around in circles, so to speak, endlessly.
we just want and need to know what is happening in the round tank, how the fish behave, especially when the tank is stocked with fish and later fished out.
but also what happens in general - where problems arise - and at what times the spawning happens, i.e. fish that are pregnant that we have to separate.
on the other hand, we want to create a process documentation - for all cases and also do research!

for this purpose we have artificial fish: they are just watercraft, submarines, which should also swim endlessly with the fish in the round pool!
we have a mini hydrogen cell as a drive for everything that has to be operated electrically - and we have provided the submarine with water flowing through it with a special, coordinated drive.
This is a rough draft that can hopefully be expanded and completed later. at least it's the case that with grabcad I can't always set everything the way I want it to - although the data was generated and completed!

step, igs, stl