In most cases you will need a chiller for trout. They are pricey, more than $600 USD, see www.BigAlsOnline.com
If you are handy there are small refridgeraters like this one for $76 USD that can be drilled and plumbed with a small circulator pump (about $40 USD) and some coils of 1/2" plastic tubing. For under $150 USD you can make a chiller that will give a 20 F degree draw down on a 200+gallon tank.
Black Kenmore 1.7 cu. ft. Compact Refrigerator
Sears item #04691179000 Mfr. model #564-91179400
1.7 cu. ft. cold storage capacity refrigerator with euro-round door styling, smooth back design and adjustable temperature control. 5-can dispenser, slide-out storage shelf and half-width freezer w/ice tray