אל תשקצו את נפשתיכם בכל השרץ השרץ ולא תטמאו בהם ונטמתם בם. (שמיני יא:מג)

Reb Yehoshua Kluger zt’’l served as the rav in the city of Greiding where its inhabitants earned their livelihood by selling non-kosher fish that they caught in the river bordering their city.  The Rav tried to coax his Yiddish constituents to stop dealing with non-Kosher fish, despite the halacha allowing one to sell it to non-Jews.  However, the Shulchan Aruch (יו’’ד סי’ קיז ס’’א) says that initially, lechatchila, one shouldn’t catch non-Kosher fish and not to conduct business with something that is forbidden to eat by the Torah.

Unfortunately, his words were brushed aside.  The Yidden couldn’t withstand their Nisoyan – test, especially since this was an easy source of income, and they continued selling non-Kosher fish to non-Jews.

What happened was “עבירה גוררת עבירה” – one sin led to the next, and these Yidden started forsaking Shabbos by working on Shabbos.  Reb Yehoshua, their Rav, couldn’t control their actions, and he traveled to Belz to Maran Reb Yehoshua of Belz zt’’l to lament over the terrible Shabbos desecration taking place in his city.

Maran Reb Yehoshua of Belz told him to return home and assemble his congregants, warning them in his name that they were forbidden to sell non-kosher fish and to stop desecrating Shabbos, or else they would face harsh punishment.

The townspeople didn’t accept their Rav’s harsh words.  A short time later, all the fish from the river disappeared, and they all suddenly lost their parnassah – livelihood.