Final answer:
The first step to acclimate the fish is to float the bag.
Step-by-step explanation:
The correct first step to acclimate the fish when plastic bags containing fish are received at the facility is option c) Float the bag. When fish are transported in plastic bags, the water in the bag may have a different temperature from the water in the tank where the fish will be housed. Floating the bag in the tank allows the temperature of the water in the bag to gradually adjust to match the temperature of the tank water. This helps prevent temperature shock, which can be harmful to the fish.