A better option is to get a low voltage DC motor for this, instead of the AC fan motor.
However, there are various knockoff of the SeaSwirl, for example, the SeaSquirrel, IIRC. In my opinion, this kind of DIY should not be done due to the problem with the motor in contact with the water. You need a good housing for it to work well, and you will also need to work out the gasket and bearing for the rotating shaft.
[Kung Fu Panda 3] Li: She was the total package: smart, beautiful, tremendous appetite