Backyard Aquaponics
A place to discuss aquaponics

Any fish will suffer above 18c and that is bacause of the water oxigen retansion is greatly deminuished by high temp, this is why I used to have insulation and shade netting, my FT was outside and still suffering, 20c in summer.
Stoking ratio it really depend upon filtration capacity/areation/max water temp/water parameter.
It's a long equation with many variables, you will master after some experience or more study.

True enough... if the flow is too great...

And having looked back at the system specs... particularly a 200L fish tank... the 4000L pump is a fair recommendation...

Not sure why you'd need a 2mtr head in a 200L fish tank configuration...



Indeed not... a seperate air pump, preferable a rechargeably battery backup air pump... is IMO.. mandatory...


Agreed again... anything less will just cause problems...


Even with apprpriate filtration... I think the tank size limits the number of fish to about 3.. when plate size... at most...

Personally... I think a 200L fish tank is just really too small... basically.. it's just an aquarium.... and not even a really big one...

That's entirely dependant on the fish species.. and/or location....

Trout might begin to suffer above 18c...

But most Australian native freshwater fish.... are only just starting to wake up.. and feed at 18c...

And northern species.. like Barramundi... are dying from the cold... at 18c....

Thanks for your input, both of you, every reference point is useful! and that's why this forum is such a great resource

I've done some back of the envelope calcuations to estimate how long a 500g carp would be, and it seems 35cm is not unreasonable.

Going by the following from wikipedia:

I should be thinking of about 4 fish maximum per tank, which ties in well with what you're both telling me.

Maybe I need to rethink the whole idea and move the fishtanks out of the greenhouse to give them more space... But the idea was to start small and self contained.

As for the temperature, I'm not an expert but I was going by the following (from wikipedia again):


I don't know what the temperature inside a greenhouse would get up to in the height of summer in London... It's rare that it gets above 30 outside, but I gather greenhouses are pretty good at raising that!

Time to look into battery backed air pumps!

For the pump size, remember this pump will be turning over two of these tanks, so a bit over 400L.

But I will look into the Fish Mate pumps as they seem cope better at higher head heights, with lower power ratings to boot! Thanks for the recomendation

Perhaps I'm worrying too much about frictional losses in the supply pipes - just make the pipes bigger.

Rup I was referring to UK native fish temperature only, my ethical mentality does not allow non native species, and Australian should know something about it non native species (cane toad case)
We had enough problem worldwide with non mative species and predatorial behave to an extend of wiping out local species, again..... human interference= extremely WRONG!!!
BIF what happen to in a car left in sunshine all day? becomes an oven!
think as your GH.

Thanks BioAqua, I guess you could consider carp to be an invasive species here, it seems it is native to Asia, but it's pretty naturalised here by now!

Thanks for the car example, but my GH will have two automated vents, a third manual one and I plan to leave the door open on hot days, so hopefully nothing like a sealed car in the sun. I plan to monitor the water temperatures and if they do seem to be going too high too often I'll introduce a fan.

It's still a concern though, so if you or anyone have first hand experience of carp in a greenhouse or poly tunnel I'd be grateful for any insight

Okay, I don't know exactly how the wood-working will go, but I'm joining up the two smaller tanks as I think that will be kinder on the fish.

It's now a 500L fish tank with about 400L GB (2 x 200L). There's a bit of space to add to that, so I can hopefully take it to at least 500L GB before the fish get large.

That gives me 16 whether I work on 25L GB per fish, or 30L FT per fish. [These figures were taken from another thread].

Now this is still a small tank, and stocking to max capacity seems like a bad idea, so I'll stock with 10 fish (the minimum I can probably get from a supplier anyway). and see how things go from there.

Does this sound better to everyone? Please tell me if I'm missing something, I'm happy to be corrected now instead of finding out the hard-way for myself later!

mirror carp, leather carp, crucian carp.....and more all native to UK do some research.
Actually have a look at this
http://www.wsangling.com/index.php?opti ... &Itemid=57
or wikypedia

Where are you getting you fingerling from in London? if you really struggle go down to FARM;shop and ask them to sell you some tilapia

Yet more data points... This article (which I haven't read all the way through as yet) is comparing the performance of carp at 64kg/m^3 and 32kg/m^3.

Granted they found that the fish grew faster and were more effiecient at converting food to weight at the lower densities, but I'm not suggesting anything close to this.

Stocking with 10 fish as I'm suggesting would be 10kg/m^3 and only that when they've all reached table size. Assuming some reach that size before others (hence, get eaten) it's likley the system will never reach that density.

Would this still be considered intensive (battery, unethical) farming? Or too high a density for a first time system, being less tolerant to my mistakes?

I'm also expecting to lose a few fish as I learn, which should bring the ultimate stocking density down... (but trying to prepare for the possibility they might all survive!).

Still a bit unsure about all this to be honest...

Ahh, I was looking at common carp, I should have been more specific, sorry.


I have yet to contact them, but I was hoping these guys might be able to supply me with some. They're not local, but they do specifically say they'll sell fish to people stocking aquaponics systems and I gather fingerlings can be sent by courier?



If you have any suggestions for places to buy small quantities of fingerlings I'd London I'd be grateful.

Sadly I've discounted tilapia as I read they'll die in water below 21°C. Even in a greenhouse I don't think I can keep that temperature up for more than a couple of months a year without heating (a route I don't wish to go down). Thanks for the suggestion though, keep 'em coming

Ahh Jimmi, yes I know them, I don't think he will send you 10 fish only, they actually run aquaponic courses too, but interestingly when I've call them they've stated that they do not run a system year round, I'm questioning about his knowledge of AP in winter months (the most crucial time!)
We have a list of supplyer but they do not sell only 10 fish I'm afraid.
just go down to a coarse fishing lake, there are a few of them in the outskirtof london.

The other option is John Wall Fisheries, as recommended by WelshDragon here: viewtopic.php?p=363087#p363087

He specifically says that they can cope with smaller orders, but only by piggy backing on a bigger order:


I will have to try calling the local coarse fishing lakes to see what they can do for me, thanks for the idea