They're fine as long as you don't feed them. The Klingon
s had gotten rid of all of them sometime between the original series and Deep Space Nine
, but then when the Defiant
went back in time, they brought some back with them. The tribbles did help Captain Kirk
find out that the quadrotriticale was poisoned, though.
Tribbles are now sold by pocket books in various colors. If you squeeze them, they make tribble sounds. And Quark came out with a pet-owner's guide. But luckily, these tribbles don't reproduce. They don't eat, either. I took one to school and found out which people among us are Klingons (i.e. they inexplicably and immediately dislike the small, furry creature) and which are not, but rather, tribble-loving, huggable people.