How to Breed Fish with Fish Ponds in Stardew Valley
Fish ponds are one of the new buildings you can add to your farm in Stardew Valley. They allow for tossing in any fish you catch with your fishing rod in the game, tossing them in so they can swim around in captivity.
To breed them, you need to toss in two of the same kind of fish into your pond. If you don't already have a fish pond added to your farm, you can go about it in a pretty straightforward way. It's not too difficult to add one to your land.
Eventually, another fish of the same kind should join the population, adding to your collection. However, fish ponds start with only three slots. You need to expand them.
When you see an exclamation point over the pond, click on it, and you'll see what the fish want to remain happy. Fulfill the task, and you should see a few more fish slots available. You don't have to fill these. If you have over two of the same kind of fish in the water, they should populate it themselves.
You can go about your activities as you normally would, and after a few days, you should find a type of roe based on the kind of fish you tossed into the water. You can choose to add them to a preserves jar to turn it into an aged roe after a few days.
You do need to keep some fish species separated. They don't want to buddy up with other fish populating a fish pond. If you're going to have multiple fish on your farm, you need to create numerous fish ponds to accommodate. Over time, you should see the fish expanding. You'll steadily be able to upgrade them all to expand your farm continually.