The short sentences work really well here, each one feeling like a penny throw. On the surface, a nice story about the irony of throwing pennies away and wishing for riches, yet an undercurrent of human nature, and how we tend to chase the short term easy feel better.

For me, the line that really hinges this is

I watch them sink to the bottom

The rise and fall of hope captured in the simple act of making wishes, it conveys so well that gutted sinking feeling, the regret that follows. Wonderfully done! <3