"The fishing system is working differently depending on the "Hz" of your screen! For now the normal speed should be at 60hz, I'm working on a solution. Thanks for your understanding.😢" - under the IMPORTANT notice on the download page
You'll have to find a way to change your monitor's refresh rate to get fish for now.
I appreciate the reply, but I've shockingly just got used to how fast it is. I have a 360hz monitor so it is VERY hard, but after the first 200 or so attempts, I can now catch fish fairly successfully even if it is moving blindingly fast haha. Though I do hope that does get fixed for the others that can't do their fishing because of this.