When I search the Yizkor Book Master Name Index for the name Fishler in the town of Gura, I get a single result:

FISCHLER, Moshe, Town of Gura Humorului, with the unexplained comment "soda water."

This squares with what little I know of my g-g-grandfather, so I'd like to find more information. From what I understand, this suggests there is a record in one of the yizkor books, but I cannot locate anything more than this indexed mention. Might someone be able to point me in the right direction?

Soda water (Zeltser) refers to the profession of the person. People would mix CO2 with water, fill  bottles and deliver to homes. The 1939 business census of Poland available in Jewishgen lists that kind of business and the name of the person/s that did it.

Look for the Town Gura/Gora in Poland