Vayikra 1:2

דַּבֵּ֞ר אֶל־בְּנֵ֤י יִשְׂרָאֵל֙ וְאָמַרְתָּ֣ אֲלֵהֶ֔ם אָדָ֗ם כִּֽי־יַקְרִ֥יב מִכֶּ֛ם קׇרְבָּ֖ן לַֽיהֹוָ֑ה מִן־הַבְּהֵמָ֗ה מִן־הַבָּקָר֙ וּמִן־הַצֹּ֔אן תַּקְרִ֖יבוּ אֶת־קׇרְבַּנְכֶֽם

“…From the cattle…”

In the Midrash Tanhuma (Vayikra, 8), the question is raised: why do we not bring fish as a sacrifice?

In my humble opinion, it appears because our Sages of blessed memory said (Shabbos 108a) that fish are particularly “contaminated”. They explicitly stated in the Toras Kohanim (Parsha 5, Section 2) that one must exclude anything “contaminated” even among cattle, for this is not a respectful way to honor the One Above. This is similar to the rebuke of the Prophet (Malachi 1:13): “And you brought the stolen, the lame, and the sick…”

Furthermore, it can be attributed to their cruelty. There is no other creature that swallows its fellow alive and whole. Even a lion at least mauls its prey until it is as if dead, and only then eats it. This is not the case with fish, who swallow one another with great cruelty (Avodah Zarah 4a). Therefore, they were rejected from being used as a sacrifice.