No you don’t have to get a whole house generator. However, you do have to be home when the power goes out with a standard generator. The beauty of the automatic home generator is it starts up in about a minute after loss of power. I have both. I have a generac that will run everything I have. I also have a portable for camping/emergency use. I work 12+hr shifts during inclement weather so if the power where to fail I may not be around for half a day to remedy it. I’ve already lost a whole tank to a long term power outage when away it won’t happen again.
There are many options for generators for any budget. Check out one of the home improvement stores that sell them and have them come give an estimate. You may be able to finance one. Or harbor freight carry’s many sizes of regulars that work pretty good surprisingly. What do you have invested into your tank vs amount of times losing power vs cost of generator. I lost about $8000+ in livestock and live rock. My $4000 generator is pretty cheap insurance.