One of DDs tops smells like kippers and washing doesn't help - what the hell is it?

[whomovedmychocolate]

We've washed it in biological washing powder and everything but it just honks of kippers. It's a really fishy smell. None of her other clothes smell - even those washed with the top and obviously I've checked there are no actual fish stuck up the cuffs or anything, so WTF can be causing it?

Also does anyone know of a cure? I'm completely befuddled as to what it can be. It's definitely a fish smell though.

I find a scoop of breadsoda in the wash is very good for getting rid of odours ( cloth nappy user here!) but have no idea what's causing it!

Ooh good idea, I can try that - I did think vinegar would do it but nope still smells of fish. It's very odd!

Prewash in vinegar? Then wash with vinegar as the conditioner?

I have a theory that if vinegar doesn't work, breadsoda will and vice versa because one is acid and one is alkaline.