ArtMetal

Stephen Fitz-Gerald
Hey Brody,
A round disc will lend itself well to scales like a fish,but with a hole in it (like washers) it'll be more difficult than full discs. They'll have to be closer together to avoid seeing the hole. The weight difference isn't that important if you weld everything solidly together.
As one who has been making sculptures from punch parts for YEARS, I recommend them as a viable alternative to washers.
Also if a fish is your theme,there's another fairly light but effective way to accomplish the look of scales. Expanded metal:
Her's a 5 ft. coelacanth I made long ago with that material:
http://ou8nrtist2.deviantart.com/art/Coelacanth-Sculpture-46217031
Good luck!