It's hard to teach something that comes so easily, especially if you can't remember being taught. But seeing as Levi has learned how to tread water for at least a few minutes without sinking like a stone, Finnick should count it as a success.

It might be a little difficult to tell in the dim light and through his look of intense concentration, but the praise and the smile do seem to boost him a little, and there's a little hint of triumph in his eyes. When he manages to stay up on his own without completely submerging, he flicks a pleased look to Finnick, and starts to experiment with different movements with his arms, figuring out how to propel himself forward.

"Yeah, all those shitting fish better watch their backs." Or something.

Eventually, he figures out how to glide forward, and moves in close to Finnick again. Take his waist again, sir.

"Thanks...had a good teacher."