You need a water supply for trout - ie if you have a lake, it needs to be one fed by a stream with a sluice etc, or on a hot day they will go belly up.
I used to be a trout farmer and the farm I started on was tiny - 12tonnes per annum from egg to table/restocking size. Can't see it being cost effective really on a smaller scale than that.
Now, carp, on the other hand....