Help me 😩

So i went to go down on my boyfriend because I haven't in about a year because he had like a fishy smell and it put me off. Anyway I thought it might have stopped by now. He just got out the shower and i couldn't even put my mouth around it. It was that bad. I've washed for him and seen him wash but the smell is still there. It's as if it's in his peehole? Ive told him before nicely and he showers everyday so I don't understand? Our relationship has died down the past few years but its gradually getting better and the spark is finally coming back!! What else can we do? We haven't got any STI's or infections.