Please visit the FDA Fish Site for just a minute. There is a Barcode of Life effort underway to post a little bit of the DNA sequence for EVERY organism on the planet. Considering we have not identified them all yet, this is pretty ambitious. A global offshoot, known as FishBOL, http://www.fishbol.org/ collects the Fish sequences. I am working with Jon, and he does the work for this site. Someone sends them a frozen fish, and it gets Authenticated by an ichthycologist. Jon photographs the right side of the fish with a color bar. Then he removes some tissue from the underside of the fish, where it would not show in the photo. Then the fish heads for the Smithsonian, where it is stored with a code (Vouchered).
So, what happens if you have several individuals of the same species of fish and you find out the DNA sequence is pretty different even though the fish looks the same to the expert? Some times it gets reclassified as a new species. That is why it is so important to keep the fish in the museum. You can get it out of storage, check it all out, and reclassify it. Pretty cool, huh?
There is also an effort underway to do the same process with zoo animals and bush meat confiscated by customs. You want to volunteer to authenticate, photograph and voucher a tiger?