Let me tell you a story of the cod fish. At the turn of the century cod fish were in much demand on the east coast. News of this tasty fish spread across the country all the way to the west coast. There was however a problem. How could they get the fish across the country and still keep it fresh.
They tried to freeze the fish and send it by rail, the fastest means at the time. When it was prepared it turn out to be very mushy and lacked flavor. Then someone decided to ship the fish live turning railroad cars into huge saltwater aquariums. When the cod fish arrived they were still alive but when they were prepared they were still mushy and tasteless.
After studying the cod fish someone discovered that their natural enemy was the catfish.
This time when the cod fish were but in the tanks they place a few catfish in with them. Those catfish chased the cod fish all the way across the country to the west coast. This time when they were prepared they were flaky and had the same flavor as they did when they were caught fresh and prepared on the east coast.
You see the catfish kept the cod from becoming stale. The catfish kept them fresh.