Another consideration is that raising the temp of cool water species affects their physiology. Amino acids, hormones, omega-3 levels are adversely affected if temps get too high to maintain proper osmotic regulation and digestion. Immune systems and blood regeneration are also adversely affected. With species such as sturgeon, it's always better practice to adjust the environment to the fish instead of forcing the fish to adjust to the environment. It's exceedingly difficult to try overriding millions of years of evolutionary-set patterns.