Bug/Issue voidfish and slimejack crashes

So I went to fish in the mutant bug lair. Only to have the entire game crash and turn off. So I tried again in the witches swamp. I caught two algae, but when the 'Hit!' prompted it crashed again. Guess Slimejack and Voidfish is out of my reach for now.

No mods on this game.

 

That sounds like an issue with the data files; strange it's happening on an unmodded game.
I'd try verifying your files to make sure nothing was corrupted.

Instructions for verifying files:
Right click Stardew Valley in your Steam Library.
Then select 'Properties' from the popup.
After that a new 'Properties' window should show up.
Go to the 3rd tab, 'Local Files', and select; "Verify Integrity of Game Files".