above ground pond

For a 50 gallon pond I would just stick with 2 or 3 goldfish. Koi get way to big for a 50 gallon pond. They can get up to 2 to 3 feet. They need a much larger pond.

Check out an agricultural supply outlet, they sell Rubbermaid tubs that range from 50 gallons to 300 gallons. These are usually used for livestock watering. They don't need any outside support like a pond liner would, you could dress up the outside however you like.

They are fish safe, I've had two 150's running in my fishroom for quite a while, and set a third one up outside a few weeks back. I'm breeding platys outside, 1,000W of heat on a controller, with a second 1,000w heater if the temps really drop. I dressed up the outside with half a dozen moving blankets & duct tape, as I set it up about a month earlier than I had anticipated. Can't pass up 50 free cichlids, they've all been sold or rehomed.

This is also my first experiment with plants, as the rest of my tanks are oriented towards breeding. I have 16 beer cups with plants in them on the bottom, in the hopes that sunlight will make them take off.

A 50 gallons is way too little for koi (my koi wouldn't even fit in it). Koi can get to be huge and need well over 200 gallons per fish. One goldfish may be able to survive in a tank that size but it will have to be filtered with at least 5X turnover of the water every hour. Goldfish like company so I think that would be cruel to leave one in there alone. I would recommend 10 White Cloud Mountain Minnows, 10 Rosy Reds, or maybe one Paradise fish.

You will also hsave to be very careful to put it in a shady location to help regulate the temperature. I worry about the cement pad underneath of it. These get really hot in the summer and could cause drastic fluctuations of the water temp between day and night.

Hello, here's what I have, somewhere between the 50-75gal range

http://www.aquariacentral.com/forums/showthread.php?t=126968

And I agree about it being too small for a Koi. Kois get huge.

Good luck

I can PM you some vendors that sell pygmies if you like. If you want something a little flashier (you will never see the pygmies in your pond), here are some options:

Rosy Red Fathead Minnows- They get much brighter than they are in the store when well fed and not overcrowded; they may even breed if you provide some flowerpots or other cave-like structures. You'll need to quarantine and cull your initial purchase to make sure you're not throwing a bunch of sick fish in. They feed readily on flake foods, and will also eat algae and insects that will inevitably grow in your pond.

Bluefin Killifish- Small, handsome topwater fish. Devour mosquito larvae. They will also eat finely crushed flake food.

Dollar or Bantam Sunfish- Larger, brighter, and bolder than pygmies; two or three would work well. Active predators on insects and small fish, but can also be trained to pellets.

There are of course plenty of other options, these are just the first that occurred to me. If you're willing to take your fish indoors in the winter you have even more options.

Stock tubs are great, but not very attractive. You could also build a wooden frame and line it with pond liner. Unmortared bricks would probably collapse.