Oh. They're carp? Carp? Man, the human race will domesticate anything. They really shouldn't.
For example, Skunks? Skunks?! Has evolution not given you abundant reason to stay the hell away from skunks?
While we're at it, can we just lump lions, tigers, wolfs, dingoes and monkeys together into the category of "things you shouldn't have in your house because they'll probably kill you"? Apparently not. (I'm not kidding about monkeys. Enjoy your Herpes B: progressively ascending paralysis, confusion, coma, multiple organ failure and a 70% death rate. But it's sooo cute.)
Or, 'Fancy Rats.' Fancy rats? Give me a break, it doesn't matter how fancy your rat is, it's still a damn Norway Sewer Rat. Seriously, the brown rat is the most successful mammal on the planet: it has established itself on every continent except Antarctica (and I fully expect to see Antarctic snow rats before long). Does this species really need our patronage?
Now the Gambian Pouch Rat, there's an example of rat put to good use. They find landmines, for heaven's sake, who could argue with that? And they detect Tuberculosis as well as a human lab technician. They're like the seeing-eye dog of vermin. That's an animal that you should keep as a pet. What? Wait, Monkeypox? Okay, nevermind.
Also, some people keep anteaters as pets. But, honestly, I'm pretty sure they're only useful for hilarious anteater-caption images (warning: coarse language).