What precautions should be taken to ensure the freshness of fish in a cooler during transportation?

To ensure the freshness of fish in a cooler during transportation, it is important to pack the fish in ice or gel packs to keep it cold. Make sure the cooler is well-insulated and keep it out of direct sunlight. Check the temperature regularly and replenish the ice as needed to maintain a cold environment. Additionally, avoid opening the cooler frequently to prevent warm air from entering.