Hello Don
I am by no means an expert as many are on here but on the first fish tales that I had there was an issue with the reel. In my case I believe it was not lining up correctly for the balls to enter and then be shot out at the right time. The solution for me, and thank you to Lisa formerly of Cadillac Music in Cleveland who diligently worked to find the issue, was on the underside of the playfield in I recall correctly. There is a small board there that controls the reel and that is where my issue was located. New so long that I can’t recall exactly what Lisa did to repair but the issue was definitely on this board.
I would not think the motor is at fault as that seems to be ok. The logic that is controlling the motor may be the culprit here.
Hope this is helpful
G