Funny you should ask. Chris Steelman recently educated me on the difference between gizzard shad and threadfin shad (other than size). Namely, gizzard shad have a "nose" and threadfins do not.

See this thread:

http://www.pondboss.com/forums/ubbthread...true#Post125882

You can also search on google images for pictures of different types of shad.

"Only after sorrow's hand has bowed your head will life become truly real to you; then you will acquire the noble spirituality which intensifies the reality of life. I go to an all-powerful God. Beyond that I have no knowledge--no fear--only faith."