>>1091269Fish nerd here. You probably didn't suffocate him so much as stress him out. Tarpons have a swim bladder that allows them to breathe small amounts of air to some extent, kinda like betta fish. Taking him out of the water for too long probably wasn't the problem in terms of that, but fish can be susceptible to stress.
>>1091328so yeah this,
Either he swam away and was fine, which honestly could have happened if he was just shocked, or he got eaten by something bigger. Or he floated off into the reeds, since fish tend to float for a bit after they die.
They aren't endangered to my knowledge so don't feel too bad. I once killed a bluegill as a kid and was utterly traumatized so I know how you feel.