This method removes blood, black layering inside of fish and bad fishy smell ever so easily.

For 1 kg of fish required is:

Salt: 2 table spoon

Vinegar:  4 table spoon

1. Add the salt  and vinegar into warm water and mix it well.
2. Dip the fish in that water for five minutes
3. After five minutes blood and most of unwanted material will be removed itself.
4. Rub the fish softy for remaining cleaning.