If I catch wild fish from clean waters and check it rigorously for parasites, can I use it as Sashim(Sushi)?

I think you have to be very careful with this.

The most important thing to remember is to freeze the fish before eating it – this kills the parasites!

A rough guide for fish that are suitable for eating raw is to freeze for seven days at negative 4 degrees Fahrenheit

You can speed this time up by reducing the temperature

Also some fish, such as Tuna can carry high levels of Mercury and can be hazardous when consumed in large quantities.

I suppose it comes down to who is going to eat the sushi, yourself or are you giving / selling it to others

If you are selling it to people, there are strict guidelines

Anyhow, when you decide to make some below is a useful guide.. Good luck!

Source(s):

http://japanesefood.about.com/cs/sushiet…

How To Prepare Fish for Sushi