For Tropical Fish Tank:
Make sure you properly acclimatize your aquatic life to help them adjust to any changes in temperature, salinity and PH.
Turn off the aquarium lights.
Float the bags for 10-15 minutes to adjust the temperature.
Then open the bag and add some aquarium water. If you roll down the sides of the bag it should float on the surface, make sure the bag is now left open.
After 5 minutes add some water to the bag.
After another 5 minutes add some more water to the bag.
After another 5 minutes release the aquatic life.
Keep the lights turned off to help them settle in and reduce the risk of aggression from established fish.
Always follow the procedure above even if the fish looks sick. Some fish when stressed do lie down but will quickly recover in the aquarium.