Self replenishing pond

Hey everyone,

I'm new here so if I break any conventions I'm not aware of please let me know and I'll sort it out.

I've just bought my first property and I'm looking to set it up to be as self sufficient as possible. I've got solar and and food forest started, but now I'm looking for an easy form of protein.

I've got a big space where I'd like to dig a pond and put some fish. What sort of set up would I need to be able to take a few fish a week by rod and line and have them breed enough to replace what I'm taking? I'm happy to put filters and aeration in as well as plants, but I don't want to do batch culls or restocking. I'm thinking if I put a grid in to separate an area where fry can go and be safe then breeding should work? Food wise- I'm raising chickens and I think it would be viable to put the carcasses in a bucket and let the maggots spawn and then throw them to the fish for a bit of protein. How big a pond would I need for this to be viable and what sort of fish would work? I live in the UK, so tilapia is off the cards for outdoor.

Thanks in advance.

I have extreme pond envy!  For breeding you'll need to make sure whatever habitat the fish need to breed is in place.  Some fish need an area of sand to lay eggs, so when you build the pond you can add some sand areas to shallow areas before you fill it.  Also put a few hollow logs in there so the fry have places to hide, and of course you will include plenty of water plants.  Some fish are so eager to breed they will do it anywhere.  We had Bluegill trying to breed in our seasonal creek.  They had washed down from the neighbor's pond during a flood and were only in our creek for a few weeks, but some were making nests in the sandy bottom.

"The Perfect Permaculture Fish Pond" https://vimeo.com/179831863

Hi John.  Welcome to Permies and congrats on the land purchase.

I was looking at something similar but, in the end, it seemed like a massive project for very little return.  I may be totally wrong but my reading led me to believe that I'd need a very large pond to be able to take fish on a regular basis.  In Canada it seems that it's best to have ponds at least 14-15 feet deep for overwintering.  

I'd be interested in seeing what it would take to do what you're looking to do, but I think I'd rather use the space and money to raise chickens, quail or rabbits if I want protein production.

If all you want is protein, I think black fly soldier larva would work well, but you've got to eat 'grubs', so it may be a tough sell

Most of the UK is warm enough that ponds don't need to be very deep to avoid freezing.  They still should be as deep as possible to avoid overheating in summer (though that's not much of an issue in the UK either).  Bill Mollison felt that aquaculture is the most productive use of land for raising food, but he was in the tropics/subtropics.  I think it may be different in a very cold climate.  In general ponds should be as large as possible, especially if there is not a constant supply of fresh water coming in.

Thanks for the responses everyone. I agree that the general consensus seems to be that its not worth it. The reason I didn't want to go in for a 'batch input/output' system is that I don't really get days/half days free, only an hour here and there (owing to the nature of my work). Originally I had grand visions of pulling a trout out, throwing a handful of feed in and walking away, knowing it was primed for the next taking. But given trout seem to need around 3 years in a 'natural setting' to get to eating size, I think I'd need around 400 fish to be on the safe side with regard to breeding. I don't think I could produce enough protein to feed that many fish.
Tom, I don't think aquaculture is the best use of land in the UK. I've been looking into it and I think the viability is largely dependent on the type of fish, usually tilapia. With the heat input you'd need I don't think its worth it.
Timothy, it was trying to find something to do with maggots that set me down this path, I don't think I could pallet them straight. I'm considering just feeding them back into my chickens. I'm just trying to make sure none of my 'byproducts' go to waste.
Thanks for the help chaps, I appreciate it.