fish climbing a waterfall
Refers to fish, especially salmon or trout, swimming up a waterfall during migration. Often used in seasonal or nature contexts.
In autumn, you can see salmon climbing the waterfall.
Kana spelling is common in everyday writing, especially when the kanji 滝 is not needed.
Compound of 滝 (waterfall) and 登り (climbing), from the verb 登る (to climb).