Need advice on how to preserve fish

[Molten Furnace]

What is the best way to keep fish for more than a few days? I have been told that if you freeze yellowfin tuna it ruins the texture of the meat. Is that true for other species as well?

Any advice on how to keep the following fish for five or more days?

• Yellowtail;
• Tuna (yellowfin and bluefin);
• Calico;
• Halibut;
• WSB

Thanks