First, red worm refers to a variety of worms, it is not a specific worm by itself. The red wiggler
on the other hand is great for small brim since one uses a smaller hook for the smaller ones. The red wiggler worm is also the best worm to use if composting food scraps...
I have a little more information I posted answering another question by you located here
Ken, there is no common earthworm as there are over 2,200 species of worms currently known to exist. Most all are not even native to the USA. Some will say none were native to the USA, however I have a difficult time absorbing that since worms are part of the environment and play such a valuable role in composting in nature.