I recently bought a Fish Tales machine and wrote to the software designer Mark Penacho to tell him how much I enjoyed the game. It's a fun theme, great gameplay and really challenging. My kids love the flapping fish which is a great gimmick. Mark Penacho is now back at Stern designing pinball machines again.
Mark was gracious enough to respond with the quote below which I am sharing with you. It has details on the design, and an unpublished tip for the video mode that will guarantee you an Extra Ball if you do it correctly. Following this tip I almost always get the Extra ball to show up in Video Mode now. I hope you find this information useful:
"Thanks for those kind words. Fish Tales was a lot of fun to make back in 1992. It was one of those games where the team really got along well together and things just fell into place. I still have mine; the fish on the top was removed at some point, and I have it in a box - I should put it back on top as I liked the way it moved. The fish was actually sculpted for the game - we had tried several rubber fish that were available, but none were the right shape and size. Little did I know back in 1992 that I would again work in pinball some 28-29 years later.
One thing I remember on Fish Tales that never quite made it into anyone's rule sheets correctly is how video mode works. It is 100% deterministic; no random numbers are used. The three rows of skiers each come out continuously; killing one or having it leave the screen starts another one as soon as the animation finishes. To get the extra ball to come out, you have to complete all three targets, a set at a time for three complete sets. When you hit the third target in the set (any order), the flags reset and tallying starts over. The extra ball comes out after the third set. If you miss it, and have time and ammo to complete a full set, it will come out again.
Have fun and enjoy your game