Sorry been really busy with work but heres a video explaining the game.
Owner of machine made it a penny machine meaning a single digit is equal to a penny..so if you deposited a $20bill your total would be 2000 under your gun. In this video they are playing $10 a shot(1000)
They dont use these in malls because this is gambling, Im pretty sure they have very similar fish arcades in mall but with different payout system(tokens/tickets)
This video is old and is the game that started the trend in Hawaii🤙
https://youtu.be/gXDxcmADwRw