- Casio Forester Fish in Time Watch

Years ago my father passed on to me his fishing watch, which was released by Casio and purchased by him in the ’90s. It is well worn and has a fantastic ‘fishing time’ function, which is what he bought it for. It shows the moon age, moon phase, moon angle, sun rise/set time, and optimal fishing time based on the aforementioned. This data is based on the longitude and latitude that can be set in the menu. It also has typical features: alarms, light, stopwatch, etc.

A largely grey and very well worn watch. The bottom display portion shows typical watch functions, but the upper portion shows a small moon phase graphic, a single fish, and a waving tide with one segment active. The screen is illuminated a bright blue.
My FT-200 with Movement Module No 1879

I’ve previously paid for battery replacements by professionals, but when the battery needed replacing recently, I figured I’d give it a try myself. For my future reference:

Remove the back plate and pull out the mechanism, getting leverage by depressing the watch’s buttons if needed. Once removed, unclip the metal shield from the plastic. Take care, for there is an extremely miniscule spring inside the watch that is liable to be lost.

There is a small clip holding the battery in place. Release it and replace the 3-volt CR2016 battery. Next, the movement can be reassembled (remain aware that said spring also has a tiny extension on one side which sits inside the movement to stop it moving freely), and an AC reset can be performed. Using a wire or tweezers or what have you, the AC pad (labelled) should be connected with the positive terminal of the battery. This watch face should now be populated. The watch can then be reassembled.

The usage manual with explanation of the fishing functions can be found here: https://www.casio.com/content/dam/casio/global/support/manuals/watches/pdf/18/1879/qw1879_EN.pdf