For those who love the science of koi feed, this article is for you!
 
"Excessive amount of dietary crude lipid generates a lipid metabolic burden for large-sized common carp and results in worsening of growth performance and feed utilization efficiency, the higher TCHO contents in serum, the higher muscle and hepatopancreas lipid deposition, and a less-than-ideal protein-sparing effect. The results revealed that an excessive amount of dietary lipid supplements (>60 mg/kg) would inhibit WG and aggravate the lipid decomposition in the hepatopancreas. Based on WGR and FCR, the dietary lipid levels of 59.5 and 70.4 g/kg were optimal for growth performance and feed utilization of large-sized common carp. This should be taken into consideration in formulating specific practical diets for large-sized common carp."
 
https://www.frontiersin.org/articles/10.3389/fnut.2021.694426/full