Red wigglers,Eisenia foetida are a type of earthworm often used in composting and fishing. They are, as the name suggests, red colored, and they are more active than other worms, such as night crawlers.
Worms are used in making compost, a type of organic fertilizer. The worms recycle food waste into a rich, dark very fertile soil used for gardening. The nice thing about worm composting is that it can be done in a small container, and thus can be done indoors. Mary Apelhof wrote a book on composting with worms called Worms Eat My Garbage:How to Set Up and Maintain a Worm Composting System.
On a more personal note, red wigglers were the prefered worm for trout fishing by my grandma, while my grandpa preferred the larger, less active night crawler. It was a fun family feud with the virtues of each type of worm being endlessly debated on each of our family fishing trips.