Clean Monday
Clean Monday is a public holiday in Greece and Cyprus, where it is celebrated with outdoor excursions, the consumption of shellfish and other fasting food, a special kind of azyme bread, baked only on that day, named "lagana" () and the widespread custom of flying kites. Eating meat, eggs and dairy products is traditionally forbidden to Orthodox Christians throughout Lent, with fish being eaten only on major feast days, but shellfish is permitted in European denominations. This has created the tradition of eating elaborate dishes based on seafood (shellfish, molluscs, fish roe etc.). Traditionally, it is considered to mark the beginning of the spring season, a notion which was used symbolically in Ivan Bunin's critically acclaimed story, "Pure Monday".
Kosher animals
Traditionally fins has been interpreted as referring to translucent fins. The Mishnah claims that all fish with scales will also have fins, but that the reverse is not always true. For the latter case, the Talmud argues that ritually clean fish have a distinct spinal column and flatish face, while ritually unclean fish don't have spinal columns and have pointy heads, which would define the shark and sturgeon (and related fish) as ritually unclean. Nevertheless, Aaron Chorin, a prominent 19th-century rabbi and reformer, declared that the sturgeon was actually ritually pure, and hence permissible to eat. Many Conservative rabbis now view these particular fish as being kosher, but most Orthodox rabbis do not. The question for sturgeon is particularly significant as most caviar consists of sturgeon eggs, and therefore cannot be kosher if the sturgeon itself is not. Sturgeon-derived caviar is not eaten by some Kosher-observant Jews because sturgeon possess ganoid scales instead of the usual ctenoid and cycloid scales. There is a "kosher caviar" made of seaweeds.
The salmon roe is also "kosher".