Houkago Teibou Nisshi

Synopsis

Sayaka holds a training session at the school swimming pool for the club to learn how to stay afloat should they fall into the water while fishing. The club jumps into the pool with their clothes on and use special flotation devices unaware that they are for single use only. The club then goes fishing for rockfish, and Hina catches some rockfishes that get snatched up by a heron. Hina notices that the heron's leg is tangled in fishing line prompting her to think of a way to get it off. The next day, the club lures the heron into a trap to hold it still so that they can remove the line from the heron's leg.

(Source: Wikipedia)