u/SkeletonEternal

Hiya, so I found this mouse on the road. I put it in a paper bag, and there was a little blood in the bag, so I'm making the assumption it was caught by a cat. I know the chances are slim of it surviving, so right now I have 3 options:
Humanely euthanise (what is the best way for going about this?)
Keep safe until death
Keep and try to save it
I'm in NZ and vets won't treat an invasive species like this-I also do not want to release an invasive species, so that's not an option.

Also-my cat is currently on antibiotics. Could I give the mouse a tiny drop of that to ward off any possible infections from the cat bite? Thanks
The fishtank is where I'm keeping it right now. I know it's not ideal, but it's all I've got.

South Island, New Zealand. Brown oysters or tawaka? Don't worry, I won't eat something I can't ID. Just curious