I beleive that the fishy sound impression
, is due to your will to get further quikly.
Understand that the piece (being a simple one) might not satisfy your expectations. This is great, and means that you will get further. My advice is :
Enjoy your playing, look at it as if you were the first one to play it. As if nobody has never heard this before.
Give your playing a speech form : Think that it is made up of distinct phrases, that each phrase has a meaning, therefor a particular effect.
The paradox in music : I beleive that once one starts playing a piece, time notion has no importance : It's the playing that structures the Time, not the inverse. You may feel like slowing down the tempo (let's say usualy at the beginning and ends of phrases - this is no rule
) . Or just chiming out the notes. You are the Time Master, the time you are playing. There's no hurry, no quick, no early no late, in relation with the external world. There's time notion only within the piece itself (relativity). Think of tempo changes inside
Volume dynamics? Another problem... You have strong fingers! but power is nothing without control... Variations in the volume give more volume, just like a black spot on a white surface, makes it look even more white. Bringing down the volume attracts the attention of the listener
gives them confidence.
Hope it'll help.
(fEZ : put you fez in your mouth!