Welcome to TFF.
Not sure where you live--east coast of US/Canada, UK, Australia...?? But if you have cold winters, you will need what may be considered an extension of your house in effect. In other words, an additional room or a separate building that is basically built like your house, with insulated walls and ceiling (and floor). The floor probably needs to be a concrete pad to hold the weight of several tanks. An electrician will run a new circuit from your panel to the building. A plumber may be able to run a new water line from an outdoor tap or something. Installing a heating unit is the simplest of all, one of those baseboard heaters. Running a duct from the house furnace to a separate building might be very involved and expensive, if even possible to connect in. An air conditioner in a window will deal with summer heat.
It might be much simpler to use a spare bedroom if you have one. If you have a basement, that is ideal because they are usually warm in winter and cool in summer (ours was anyway) and with a concrete floor there is no worry about weight.
I moved into my present house several years ago, and one reason I chose it was the enclosed carport which I felt would be an ideal fish room, and I was right. Insulated, baseboard heating, on a concrete pad, connected to the electric panel...all that is missing is the direct water line, but that is easily got around in a house with a Python for water changes.
Byron.