This is the 5950th most frequent Japanese word.
よみがえる
"To be resurrected, revived, or brought back to life or memory."
In this sentence, "よみがえる" is used to describe the phenomenon where old memories come back into consciousness, like being brought back to life.
古い思い出がよみがえる。
Old memories are revived.
Here, "よみがえる" is used metaphorically to express the feeling of energy or spirit being restored.
彼の話を聞いて元気がよみがえった。
After hearing his story, my spirit revived.
In this case, "よみがえる" refers to the physical recovery or revival of the fish.