What species of fish that are good for sushi? Can it be previously frozen or must it be totally fresh?!
Answers: Most types of fish can be used for sushi. generally sushi is made from salt water fish. The fresher the fish the better. Freezing fish (especially red fish such as tuna) causes a change in color that is visually displeasing (browning or paling). Frozen fish are often treated with chemicals to correct their color. I would suggest that you go to a fish market and ask the fish monger what he has that would be good for sushi. Don't go in with your heart set on a certain type of fish. If the sea bass is fresher than the yellow fin, then you should have the sea bass. If you are not used to eating sushi, then you should stick to mild tasting fish (yes, tuna is mild). If you are more used to sushi then you can experiment. When in doubt, smell the fish. If the fish has a displeasing odor, it will have a displeasing taste.
Yellow Fin Tuna probably tops my list. Sure it can be frozen it just wont be as good as a fresh one.
Salmon. It can be previously frozen.
Tsk, tsk, sushi quality fish should never be frozen.
Fresh yellow fin tuna & pink salmon
Previously frozen, yes some of the fish is previously frozen.
Tuna is typically sold frozen.
Fish for sushi should always be fresh, unless you are making it at home...in which case, use whatever you want.