@Baronoflight
Does this even count as Isekai? He didn't die, get reincarnated, or get otherwise summoned or magically transferred to a new world. He was a space traveler that crash landed on a planet. Star Trek doesn't become an Isekai just because the crew discovers a new planet. Sci-fi, yes. Fantasy, yes. Isekai, no.
@Nicromatic
Especially not freshwater fish. This wasn't even the sea, just an inland river. Don't try this at home without your own nanobots, lol.