Seeds smells of fish.

A mate has some seeds planted in rockwool cubes and heated propergator. The rockwool is soaked in water and veg nutrient, they are about 4 days old and they have started to smell a bit.
Is this normal or are they starting to go mouldy?
Any ideas guys ?

Why did you soak them in nutrient solutions?
Anyway, fish smell generally means bacteria, but could just be normal... How do the plants look?

I have advised to flush with fresh water and the smell has gone. They are not yet plants but 4 day old seeds.
Thanks for the reply.

Could have been the nute solution as well, especially if it used fish emultions in it...