Unusual film about a guy with a super power related to water

This may be a foreign film; it felt like it, but I can’t remember if there were subtitles or if the audio was in English. Anyway, it seemed to take place in some sunny village, and there was a kind of ordinary-looking guy who somehow discovered that he got stronger in the water. He kept spending more and more time in the water, and then he was interested in a girl in the village, but he doesn’t tell her about his secret at first. I don’t remember this guy being interested in fighting crime or any other ambitions. He mainly wanted to keep his secret and be left alone to swim. I can’t remember much of the plot, but I think he might have worked a construction job or something like that. And at some point he is being chased and he keeps finding pools and cisterns or troughs to hide in to recover his strength. He was a very non-confrontational hero. I feel like the title might have been something very plain and prosaic, like “__?__ is a Fish.” Help?