TIL A sturgeon's sex can't be reliably determined until 5 years of age, which leaves caviar farms with the significant expense of inadvertently raising males.

https://youtu.be/tdTO75LLs4c?t=123

https://www.reddit.com/r/todayilearned/comments/15mizdd/til_a_sturgeons_sex_cant_be_reliably_determined/