chained_bear commented on the word mackerel-snapper I get the fish-eater thing, but I don't know why non-Catholics wouldn't want mackerel--evidenced by the use of the term in a disparaging phrase. (Or wouldn't want snapper, for that matter.)
Psalm 1 is the first of the Psalms in the Hebrew Bible. Like many of the psalms, it contrasts the  righteous  person (tzadik ×¦×××§) to the wicked or ungodly (rasha` ×¨×©×¢) or the  sinner  (chatta' ×××).
The psalms had an enormous influence on folklore and served as the source of many proverbs. In the Middle Ages the psalter was the chief textbook for the mastery of reading. Methodius is credited with translating the psalter into Old Church Slavonic (ninth century).