Virtual Villagers Tips & Tricks, Walkthroughs, Guides, Hints and HelpLast Day of Work Official Forums: Virtual Families, Virtual Villagers, Fish Tycoon
All of the collectible items - including fish - could appear at any time in your game. They are programmed to be random, so we can't say exactly when you'll find this specific fish, but keep checking into your game and it will happen!
It's like an Easter Egg Hunt. I check the game even when I know there is nothing else I can do at that time...just to look for that last fish. I bet its beautiful!