Why are these rain coats called Fish Slickers? Good question and here's the answer. Called fish slickers in the 1800's because they where made out of sail cloth. The ones we sell are made similiar with a cotton muslin undercoat and are waterproof. In 1844, Charles Goodyear patented a black rubber coated muslin material that was used to make various water resistant clothing such as rain coats and ponchos. In 1881, Abner J. Tower developed his Fish Brand mustard yellow Pommel Slicker. The material was basically what many of us have known as oil cloth. It was more flexible than the rubberized material that Goodyear patented and was more desirable. The slickers frequently were made with corduroy collars and pocket trim. The Pommel Slicker had an extra piece that buttoned on to the front which covered the saddle pommel thereby providing better protection for the rider and saddle. Tower also made a black rubber rain coat but it was said to spook the horses more than the yellow.