Maintenance minder symbol

[drmcw]

I have a 2013 Civic 1.6 diesel and it's nagging me to do something and it doesn't seem to have a code in the maintenance minder bit just a symbol like the usual symbol for brakes (0) but where the circle is filled with a choppy sea.

I'm guessing it means change the brake fluid as that's supposed to be done every 3 years and it's just about 6 years old.

Anyone know if I'm right?

Thanks

mike