I like the game and the simplicity of it!
I feel like it could do with some music and sound effects to be more interesting. I'm not sure what the point of the military upgrade it and what the goal is once I've upgraded everything and got a lot of money. I think some kind of reward or unlockable item/area would be cool. It's kind of boring once you're generating all of these fish, since there's not really a reason/goal to keep going.
I also noticed that when you reached 10k fish, the last number appears under itself and it looked kind of awkward so I'd either size the text down or change it so once it reaches 10k, it goes to like 10.5k, 25.8k type thing to keep the text short.