Orange roughy is a New Zealand fish with firm white flesh and a very mild flavor. It's also low in fat.
Any white-fleshed, mild-flavored fish such as flounder, haddock or whitefish can be used in place of the orange roughy.
One pound of frozen wrapped fish will thaw in the refrigerator in about 24 hours. To quickly thaw frozen fish, place the fish in a tightly sealed plastic food storage bag; place in cold water, allowing about 1 hour thawing time per pound of fish.