What do you do when half your guppies tail is missing?

If half of your guppy's tail is missing, first assess the tank environment for any sharp objects or aggressive tankmates that could be causing injury. Ensure the water quality is optimal, as poor conditions can hinder healing. Provide a stress-free environment and consider separating the injured guppy if necessary. Monitor the fish for signs of infection and consider consulting an aquarium specialist or veterinarian if the injury appears severe or does not improve.