diff --git a/share/completions/grep.fish b/share/completions/grep.fish
index 0070661da..c8e164353 100644
--- a/share/completions/grep.fish
+++ b/share/completions/grep.fish
@@ -4,8 +4,8 @@ complete -c grep -s B -l before-context -d "Print NUM lines of leading context"
 complete -c grep -s C -l context -d "Print NUM lines of context"
 complete -c grep -s b -l byte-offset -d "Print byte offset of matches"
 complete -c grep -l binary-files -d "Assume data type for binary files" -x -a "binary\tBinary\ format text\tText\ format"
-complete -c grep -l colour -x -d "Colour output" -a "never always auto"
-complete -c grep -l color -x -d "Color output" -a "never always auto"
+complete -c grep -l colour -f -d "Colour output" -a "never always auto"
+complete -c grep -l color -f -d "Color output" -a "never always auto"
 complete -c grep -s c -l count -d "Only print number of matches"
 complete -c grep -s D -l devices -x -a "read skip" -d "Action for devices"
 complete -c grep -s d -l directories -x -a "read skip recurse" -d "Action for directories"