Must be quite an experience being underwater and seeing shapes. I recall that one of the diving sailors on Jacques Clouseau's Calypso was a painter and he took his oil paints down with him to try to capture what he saw -- probably around a reef or somewhere at a depth where there was some light still. But the problem was, when they covered his gallery showing, was that the colors were so off because of being underwater changing color selection and so on, that it was all too abstract for anyone to want to buy one. So he ended up selling nothing. But it was a good try. Working from your recollection and painting in the surface world is probably a whole lot easier.
"Not a bit is wasted and the best is yet to come. . ." -- remembered from a dream