I did two for the first time this year! One 40 gallon stock tank on the patio, and one 125 gallon preformed pond. Would not recommend preformed ponds with any sort of area that juts out like a wing as they are nearly impossible to level. I lost serious spouse points when the first try wasn't satisfactory and we took it out and started over.
I was terrified putting the fish out. Everyone says this works, but actually putting fish in the great outdoors yourself is something else.
40 gallon tub: I have a papyrus, sweet potato vine, anacharis, and a tropical water lily. Got some leopard ramshorn snails by accident with the water lily, which I am super excited about. I added 6 Indian Ricefish (Oryzias dancena). They've been breeding like crazy inside, but I haven't been super successful in raising fry. None survive in the tank with the parents, and I'm not well set up to hatch them and grow them out. Two fish had an accident with an empty planting basket that I was using as a riser. The holes in the mesh were just big enough/small enough for them to get stuck. It was a male and a female so I think maybe they were spawning. We tried to rescue them but there was too much damage. Lesson learned... I also lost one that didn't look too good when I put her in, so I think she was on her way out anyway, though she made it through most of the summer. Everyone else is thriving, and there are literally hundreds of fry. I also threw in water lettuce from my indoor tank where there were still some ricefish and also some Emerald Dwarf Rasbora (Celestichthys erythromicron) who have been spawning like mad, so I think I have fry from both. Very hard to tell from above.
125 gallon pond: Papyrus, sweet potato vine, water sprite, and a tropical water lily. Also some "bonus" leopard ramshorn snails in here. I added 6-10 Least Killifish (Heterandria formosa). This was originally supposed to be the wildlife (frog, dragonfly) pond, and I was hesitant to add fish, but I couldn't find any concerns about aquarium fish transmitting disease to frogs, so I couldn't resist. I knew I might lose some fish to dragonfly larva, but figured the livebearers might reproduce fast enough that it wouldn't be an issue. I have no idea what I have for least killifish numbers right now. I made a couple caves, and I think they spend most of their time in there. I'm confident I have some. It will be interesting to see when I catch them in the fall if I have hundreds or 6-10. I've also been adding water lettuce from the indoor tank and the 40 gallon tub to this pond, so I have a bunch of ricefish and rasbora fry. We also have 4 resident green frogs, and a bunch of tadpoles which has been fun. Still working on the landscaping around this so I can hide the edge and make it more part of the garden.
Things I learned in my first year of outdoor fish:
- It works!!!! That totally justifies me getting an third (and fourth?) tub next year!

- It is really as low maintenance as everyone says! Mother Nature even took care of my water changes this year.
- I love having the ponds out there. I've been working from home. Before work, mid-day break and after work I go check on everyone out there. I've always been one to sit around and stare into ponds and creeks to see what's moving in there, so this is perfect.
- I was disappointed in how much I see the fish. The least killifish have pretty much hidden. The ricefish too, though there may not have been enough of them to feel comfortable. Since I don't tend to have super colorful fish, they don't show up that well either. From the side in a tank is very different from looking down on them with a black pond bottom. I'm itching for some colorful medaka ricefish now, but they are hard to find locally and so expensive to order.
- Water lilies are not going well. I got a late start with them, and maybe haven't fed them enough. They keep getting holes in their leaves and then the whole leaf dies. I don't see any sign of pests, and I don't think the ramshorn snails would do that? I've seen some reports of similar issues when there's water droplets on the leaves and the sun hits, but I think my leaves dry off before the sun hits them. Just hoping I can keep them alive long enough to overwinter them successfully.
I'm super tempted to just move the 40 gallon tub into our sunroom for the winter, but I'm not sure that's going to fly with the family. I'm already going to try to overwinter the papyrus and sweet potato vine inside, so why not the whole tub?
Next year I will work on making everything look a little more aesthetically pleasing, but for this year I'm just so happy it worked and everything seems healthy! Photos of various stages and inhabitants and struggling waterlilies attached.