Aquaculture question

[Chris L]

Didn't know who else to ask, but if any group can figure this out, ERE can.
I've acquired a 1,500 gallon water cistern. I was going to use it for collecting rain water for gardening, but it's massive. It's about 3.5 feet in radius and about 5 feet high.
I was thinking I could make it dual purpose and a bit of an experiment too. I was thinking I could hold rainbow trout in it and then siphon off water with a garden hose from the bottom (thereby cleaning off the fish poop) and adding this to the garden. I only have about 200 sq ft of garden (good size, but not huge) so I'd never use up nearly all the water and would continue to top it off with rain water.
I'm located in Southern Ontario so we get temps in the 30's for about 1 month (mid July/August). Rainbows like temps below 20 degrees (max tolerance) and need about 9 months growing season.
If I got them early March or so, I'd hit the peek heat season before they were fully mature, but once into Sept, temps drop again.
So any idea if this would work without major input? Would the water need any cooling if I kept it in the shade? Obviously I would need to aerate the water, but was hoping the shear volume of water would prevent it from getting too hot.
I think I might just house 5-10 fish anyway. It would be a bit of a joke anyway.
I added a photo:
http://i33.photobucket.com/albums/d60/b ... 9428_n.jpg

[George the original one]

I think you'd need circulating water to keep it oxygenated and that it's not large enough for the summer (shading might help). The trout display pond at a nearby hatchery is pretty large...
On the other hand, the fisheries research labs use containers starting at about 1500 gallons. However, they circulate water in them, usually pumping from the nearby waterways.

[Mo]

If we're only talking about 5-10 fish, I'd give it a shot. If they get warm and start looking weak, maybe harvest early.
I've never lived north of Indiana. Wouldn't there be a risk of that freezing? In Indiana and Ohio we'd routinely get ice thicker than a foot on a 1.5 acre pond. If you have that cistern above ground, it would seem that it might freeze solid, no?

[Chris L]

Yes I do think it would freeze solid. We probably get about 2-3 feet of ice on a good winter. I would think it would freeze right into the middle with enough time. It's not so much the cold, but the oxygen that would matter. 5-10 fish is what I was thinking, and there's no reason I couldn't eat them at around 5 months. That would be a decent amount of growth. I might just do some water temperature readings this summer and see what happens. I haven't totally figured out how to incorporate it into the backyard. Like I said, it's huge so would take up a lot of space. Now if I could tuck it away in the back and not collect rain water, then I could just use it like a big fish bowl. Keeps my mind busy anyway I'd like to know what above ground pool temperatures reach without input. I think that would help me a bit. I know inground pools reach about 70-75 degrees for much of the summer. Most people resort to some form of heating to make the pools tolerable.

[Sven]

An interesting idea! Don't forget to avoid fishes getting flushed into the garden though.
You might consider adding some plants in the cistern too. This should help to keep the quality of the water high (adding a filter is probably too hard).
Another thing to consider is insulation, this might prevent overheating/freezing of the water.

[dotdot]

For something slightly more involved: Another thought would be to recirculate the water from the fish tank through a hydroponic system. This might work if you want to do a more elaborate covered growing area and have a way to either passively (I'm thinking a solar water heater) or actively heat the water for your tank.
There are biofilters and things available to help provide oxygen to the water or you can use pond-type recirculating systems. You might also consider burying part of the tank, if at all practical, to help regulate the temperature. I don't have any experience with doing this in areas where freezing is an issue, though.
Also, I would echo that tilapia seems to be a popular fish for this sort of thing, but you might also consider koi as a test run because they can handle a wider range of temperature. If you have an interest in breeding fish (and there are people who want koi for pets in your area), rather than eating them, this might be an interesting alternative...

[Chris L]

Tilapia is an indoor species (so I read). Needing temps higher than 24 degrees. I would find it easier to keep the temp below this than above it. Might work well for someone more Southern though!
"Tilapia require temperatures above 24 C in order to thrive. Their fast growth means the fish reach maturity at only a few months of age, and as such can produce several broods each year, unlike our cold-water species, which typically only produce one brood per year.

Tilapia are stocked in tanks at very small fingerling sizes less than 2 grams supplied from a Canadian hatchery breeding stock. They can grow to 45 cm in size and up to 2 kg in weight, however market size fish of 200-400 grams are preferred for the live markets. Growth from fingerling to market size typically takes less than 10 months in land-based rearing systems."

[Riggerjack]

First thought was oxygen, then temps, then crayfish. they are naturally scavengers, damn tasty, and found in cold rivers to hot boggy swamps, so temps shouldn't be as much of an issue.
there's plenty of info out there for crayfish(crawdad, crawfish) aquaculture. best of luck.

[peterk]

I dunno Chris... Sure it would be an interesting hobby and experiment, but it's going to take dozens of hours setting up and maintaining that could much more easily be spent down at the local fishing hole
Two things I could think of being main issues. The temperature fluctuations, which has been discussed, and the size. I know it's pretty big, but native cold water fish demand high quality water and lots of it. If you really want to try raising your own trout I would think a dug, 5000 gallon + pond would be a much more suitable setup for trout. You'll also need to employ a filtration system.
http://www.practical-water-gardens.com/ ... garden.htm

[pathguy]

You could always bury the cistern at least halfway, then build a cheap greenhouse around it. The greenhouse would help keep the water warm, and the water would help keep the greenhouse warm enough for plants.
You could always include some more barrels of water in the greenhouse to absorb more heat during the day.
And just keep a small pump going to continually circulate/oxygenate the water.
You might want to look into Aquaponics just to get ideas, even if you don't want to do it. You circulate the fish water to beds of plants and the plants use the fish waste as fertilizer so you don't need to filter the water any other way.
Check out this system, it is a 1500 gallon cistern: http://backyardaquaponics.com/forum/vie ... 5&start=60
I'm definitely not telling you to build a greenhouse that huge though, you can buy 10x12 greenhouses for a couple hundred bucks.

[Chris L]

My biggest problem is that I barely have enough room for the tank itself. I have about 200 sq ft of garden and a coach house all in the rear yard! If I had more room I'd have more garden and dig a pond Pretty neat set up on that link.