I found it by checking these documents and doing some trial and error with various environment variables that may be responsible for this function. Environment variable - fish_color_search_match
and the solution changes the variable as:
$ set fish_color_search_match --background='333'
Where '333' is the color code. You can also use predefined colors, such as cyan , green , blue , etc., which are available.
Also, I know that maybe this is better for Unix and Linux StackExchange (what could be the reason for the lowering of votes?)
Change: Note that colors will not look right if your terminal does not use 256 colors.
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