From Pendemonium.com:
Why is it called "Noodler's"? "Noodler's Ink"? The ink with the catfish on the label symbolizes a southern sport that attempts to equalize the struggle between man and animal in the quest for a sense of fair play...and thus a fair price. 100% made in the USA from cap to glass to ink and bottled with care by Nathan Tardif in Massachusetts.
Noodler's Black ink is waterproof and fraud proof and cannot be altered on a check or envelope by rain or bleach/ammonia. It consists of over 97% water content, rinse or simply rub off lucite/celluloid/acrylic/ebonite pens. If dried in the bottle it can be reconstituted with tap water, but once on cellulose paper it will stay on as a bulldog biting the leg of the enemy despite rain/soaking and the soaps of a check forger. One word of caution - if mixed with conventional ink the fraud proof ink WILL REVERT TO CONVENTIONAL INK and all those properties will be lost. It is a delicate formula best left alone if one wants the features to remain constant.
After extensive testing, the Noodler's formula resembles 1950s Skrip and Quink ink - no feathering and a good safe ink for all of your pens. Thus an ink one can use on the newspaper crossword puzzle, most recycled smooth papers, and even card board and industrial brown paper, rice paper and tissue thin papers from the far east. Feathering has been virtually eliminated (unless you use paper towel or blotting type materials!)