No, discharge is not 'illness', A worrying change in discharge such as colour change, smell or lumpy apperance can be a symptom of illness but discharge in itself is not.
All fertile aged women have discharge at and it changes consistency throughout the month being most obvious around ovulation but it is constant. You vagina doesn't cease lubricate same way your eyes, nose, mouth and other internal membranes don't take random breaks without a medical concern. Its part of the immune system and aids functionality. NOT having it is in fact a medical issue that can have lot of complications.
I say this because in my medical experience people who claim they 'don't' have discharge very much do. They are usually either embarrassed and lying (unnecessary especially on an anonymous forum where no one even asked you) or seemingly just blind/in denial to it (slightly concerning).
As a statement its the same as someone saying to their doctor that they 'don't produce saliva except on the second weekend of the month'. It would be bizarre thing to make up and if genuinely true a baffling problem that needs prompt investigation.
Remember everyone laughing at Prince Andrews lack of sweating... same thing.
I once had a woman tell me (think it was on babycenter) that she had no discharge because he body 'swallowed it into her stomach' the same as with 'drool'. She was utterly adamant regardless of biology being explained to her by several people. The lengths people go to to hold up a lie is strange and bordering on the line mental health issues sometimes.
But no one mentioned smelling like fish by the way.