Why do Chazal state “its form is similar to a fish”?

A short introduction is necessary here: When Chazal compare things one to another, the comparison needs to be understood in context. For example, if the identity of the ארבעה מינים were to be forgotten, and we would try to determine their identity from the clues provided in the Gemara, we would look for a Lulav on a tree that possesses a לב (heart), an Esrog fruit that has a חוטם (nose), and Hadassim that look like a שלשלת (chain)174. We would almost certainly fail at procuring the correct species. Only once their identity is known to us, can we explain what Chazal meant when they used metaphors such as ” חוטם” ,”לב ” and ” 175 .”שלשלת

Similarly, Chazal’s descriptions of the חלזון need to be understood in context. This was not a list of characteristics intended to assist
someone in identifying the חלזון . The חלזון was a well-known creature to Chazal and the people of those generations176. These descriptions
are meant to accentuate a certain characteristic of the חלזון , not to identify it.

שו”ת חכם צבי )סימן נו( ” לומר על שאינו דומה דומה דרך הוא לומר אף דלא דמי כ”כ כאותה שאמרו תכלת דומה לים…”.

“…To say on something that is not similar that it is similar, is the normal way of speaking, even when it is not so similar, as they said תכלת is similar to the sea…”177

שו”ת חוט המשולש )סי’ כג( “וידוע שלשון דומה הוא שאינו לגמרי רק דמיון קצת ]כדאיתא סוכה ל”ב א’ דומה לחרות ועי’ פרש”י ז”ל שם[“. )והובא גם במשכנ”י או”ח סי’ קנו(

The terminology דומה is used by Chazal in many ways, and changes based on the context. For example, the term דומה לים appears in several different contexts in Chazal:

1( סוטה )יז ע”א( מנחות )מג ע”ב( “תניא, היה ר’ מאיר אומר: מה נשתנה תכלת מכל מיני צבעונין? מפני שהתכלת דומה לים וים דומה לרקיע ורקיע לכסא הכבוד”.

2( מנחות )מד ע”א( “ת”ר: חלזון זה – גופו דומה לים, וברייתו דומה לדג, ועולה אחד לשבעים שנה, ובדמו צובעין תכלת, לפיכך דמיו יקרים.”

3( מסכת שמחות )דרבי חייה פרק ב( “העולם הזה דומה ליבשה, והעולם הבא דומה לים. אם אדם מתקין לו ביבשה, יש לו מה יאכל בים, ואם לאו אין לו מה יאכל בים.”

4( אוצר המדרשים )אייזנשטיין – מעשים עמוד 352 ( “ואמר רב לשונו של אדם דומה לים, מה הים עולה ומתגבר אף הלשון עולה ומתגבר, מה הים יחרץ אף הלשון יחרץ, מה הים מסעיר וכו'”

In each place, the comparison is to a different aspect of the sea, and not necessarily the color:

#1 refers specifically to the color of the sea as compared to the sky.

#2 is unclear from the text itself in precisely what way it is similar to the sea.

#3 refers to the sea as the place where one goes to on a journey.

#4 refers to many other aspects of the sea – the waves and the storms etc.

Even the two regarding תכלת are not in the same Braisa and were not said by the same תנא . One cannot say that all Braisos that say the word דומה must be referring to the same aspect of .דמיון

As far as the statement of וברייתו דומה לדג , it is clear that Chazal are not describing the חלזון as being a fish. Were they to be describing an actual fish, they would not say “it is similar to a fish”, just simply “it is a fish”! Furthermore, they would not say that only the form is similar to a fish. So we are clearly talking about something that shares characteristics with a fish, but it is not actually a fish178.

Moreover, we have already brought much evidence from Chazal, Rishonim and other sources to ascertain that a חלזון is a snail. (See pg. 17.) 179 As such, regardless of how we identify the חלזון , it must be a snail type creature. This being the case, Chazal are essentially stating: “This snail is similar to a fish”. As we know, snails are not very similar to fish at all. So what could they possibly mean?

Rashi and Rabbeinu Gershom explain the word ברייתו to mean – “its form”180. As we explained, when Chazal describe something as דומה – similar to something else, they mean that it has some aspect of similarity. The fusiform shape of the חלזון is strikingly similar to that of a fish. This can be contrasted to the shape of other snails found in the sea (and particularly those found on the shores of Eretz Yisrael), that lack this similarity.

Bottom Line: The descriptions of Chazal fit well with the Murex as explained by Rishonim.