I need to make a shell for a homemade aquarium pump.
I am EXTREMELY new to this 3D printing world and I am not familiar with realistically anything to do with 3D printing.

But here is my question; I need to build a shell for a DC motor that will be powering a water pump. The motor will be submerged in water for long period of time 1+ year. I need to make sure that water does not get into the enclosure or else the pump will burn and I will cry.
What filament or material or really whatever, would be best for me to use to make said enclosure. It is brutally important that it is 100% water proof and does not dissolve in water.

Thanks!