A whale would be a really good pet if you owned your own private lake or extremely large closed off body of water. Even a pet rock would be too much for me to handle. I’d probably lose it.
My opinion: if you own a bird feeder, you can have fifty birds and you don’t have to take care of any of them. If you forget to fill up the feeder the birds can find somewhere else to eat.
A turtle would be the absolute worst pet as you have to clean their tank daily, fill up their food, fill up their water, and take them on walks. It’s like a dog but more work. They also live to 70 so you’re kind of stuck with it.
I love cats because they’re fairly simple to take care of and will try to make sure you remember to take care of them, like reminding you to feed them.
Best would be a dog. As long as you aren’t a clueless owner.
Worst would be catfish, since they get super huge and, like all aquatics, are insanely hard to care for