barley straw and barley seed help control the algae
We have around 40 koi, over 50 goldfish, about a dozen bull minnows, and one lonely blue crab in our 7700 gallon "pond." My other "pond's" liner was about to fail, so I pulled the pool liner out of the boat and set it up combining fish from both "ponds" into one.
There is no filter or heater on it. I have enough work to do and do not want to add to our power bill. I also know from being a one time aquarium hobbyist how to get the water balanced. I did it in the 750 gallon pool, and it will be even easier in this much larger pool.
Because it is not filtered, the water is more natural looking and not crystal clear. We see them when they surface to feed on the pellets, and they put on quite a show for us. It's entertaining to see them jump out of the water!
I use barley straw to keep the water clean. As it breaks down, it releases a chemical that helps control algae. I change the water by taking water off of the pool to water my garden and add fresh water back into the pool. So, it's an aquaponics kind of deal.
A few years ago, I set up a 10' x 33" metal tube frame kiddie pool near my biggest garden for water storage. The plumbing to the garden was in the works but not finished. Emily and Hannah wanted to be done with their aquarium, so I took the FIVE goldfish and put them in the pool. I hoped they would serve us by eating mosquito larvae. I didn't think they'd survive the winter.
Two seasons later, we had 46 confirmed fish with others that were discovered when we drained it. There was well over 50 fish in the "pool pond." They survived on bugs that would land on the water. I also learned they will eat algae. We fed them now and then, but we mostly forgot about them. It was so effortless; I am amazed at how it worked out!
Can we raise koi? We're going to find out! If we do, can we sell enough of them to make it worthwhile? We wouldn't need to sell many because our costs are very low. If that works, we'll spend some money on better genetics and see if we can sell those.
The blue crab. Our two younger girls caught it at our river. They asked if they could put the thumbnail-sized crab (a "crab seed" :-) in our pond. We told them they could, but it would probably die. Well, the "seed" sized crab is now about as big as my palm! I think I see another experiment in the making! Try something new! You never know how it will turn out!
If you were to visit, and we talked about the pond, Hannah would quickly tell you that after working hours in the garden on the hot afternoon after it was set up, I picked her up and tossed her in the big pool with the fish to cool her off. She was laughing the entire time until she got this look of apprehensive wonder on her face and said, "Oh my goodness! I just felt the crab run over my foot!!" (She had boots on.) LOL! She'd also tell you I couldn't get her back out because the pool is so tall. We had to enlist Clint's help!