Very interesting question! Before I answer it, allow me to express condolences, prayers and sincere wishes for a complete and speedy recovery to all who are affected by this horrific natural disaster.
Regarding the fish in the Biblical flood, we are taught that the various types of fish survived the flood — despite the fact that we are also taught that the flood water was scalding hot.
This apparently contradictory information is resolved by Nachmanides (Rabbi Moshe ben Nachman 1194-1270, Spain and Israel). He gives two possible answers in his commentary to Gen. 7:23.
- The scalding water was in streams (like the Gulf Stream) above the continents only.
- Even if the boiling water was in the oceans, it would rise to the top (because heat rises) and the fish could escape to the depths for the 40 days.
Although the second answer does not seem to explain how sea mammals such as whales and dolphins who come to the surface to breathe were saved, one might suggest that Noah took these specific species onto his Ark.
Thank you for your fascinating question, and let us hope that our own “flood” of love and kindness will one day soon engulf the globe, and that “the earth will be full of Godly knowledge, just as the waters cover the ocean.” (Isaiah 11:9)