Does fish blood have a smell, how to remove it?

Question

truly fresh fish should not smell of anything except sea water. I've been buying fresh sardines however when I take it out of the bag there seems to be a smell, it seems to be originating from liquid, blood, and the fish. even after cooking i can sometimes taste this smell.

Note this smell could be from blood, paper wrapping or something else but i think its the fish and blood.

1. with fresh fish which shouldnt smell of anything except sea water, is it normal for its blood to smell?
2. does one remove the smell by thorough washing or does it need to be heated to a particular temp to remove, if so what is the temp?

also I notice larger fish like mackerel on the fish counter look clean to begin with, why don't they have blood over them or emit this same smell?

thanks

Answer 1

truly fresh fish should not smell of anything except sea water

While that might be true of most fresh fish fillets, fish guts most certainly smell, and unless all of those little guys have been opened and cleaned, you're almost certainly tasting/smelling the guts. The big fish in the case are nice and clean because they're gutted and washed. Often, smaller fish like Sardines are sold whole without gutting and washing. This can be kind of a dicey proposition if your store doesn't do a ton of volume, or you're not super close to the port at which they were caught.

Are you removing the guts and washing them before you cook them? That would be the first step to reduce the flavors you don't like.

Is the thin flesh of the belly deteriorated, perhaps even with the guts falling out? This is called belly burn, which occurs when the guts were left in too long and start to digest the fish from the inside out. These fish should be discarded (or used as bait if you decide to go DIY)

Answer 2

There are a few possibilities. Larger fish are usually cleaned almost immediately, but smaller fish are usually not. Cleaning the fish as soon as it's caught helps remove many of the gut bacteria and enzymes that break down the fish and contribute to the fishy smell.

The fishy smell is caused by the release of http://en.wikipedia.org/wiki/Trimethylamine, and casein in milk binds to it, helping to reduce the smell.

Make sure to pat the fish dry before cooking it.