How long can you leave a fish in the bag buy it before dies?

It is not advisable to leave a fish in the bag for a long period before releasing it into its new environment. Fish need access to oxygen and a stable environment to survive, and keeping them in a plastic bag for an extended period can cause stress, injury, and even death.

Ideally, you should release the fish into its new environment as soon as possible after purchasing it from the store. If you must keep the fish in the bag for a short period, ensure it receives enough oxygen by leaving the bag partially open or by blowing air into it occasionally. You should also keep the bag cool and out of direct sunlight, and avoid handling the fish unnecessarily to minimize stress.

The exact amount of time a fish can survive in a bag depends on several factors such as the species of fish, the size of the bag, the water quality, and the temperature. Some hardy species may survive for several hours in a bag, while more sensitive species may start to experience distress within a shorter period.

To ensure the well-being of your fish, it's best to handle the transport process efficiently and release the fish into its new environment as soon as possible.