Backyard Aquaponics
A place to discuss aquaponics

Hi everyone,

I am wondering how many Jade Perch can be kept in an IBC fish tank?

Now before anyone starts quoting filtration/media per Kilo of fish let's just imagine that that is not a concern (enough bio filtration that the fish could be stacked in the fish tank on top of one another).

So I guess I am asking what seems to be the maximum amount that is humane and allows the fish to remain healthy and not too stressed? also where a SLO will remove the solids created and where adequate aeration can be added through just air pumps and returning water flow (no injected oxygen).

Let's also assume the fish will be harvested at around the 500g size

Thanks in advance

Thanks Charlie,

That's an interesting read about what is humane and that aspect of it... but what about the other factors then like disease and oxygen levels, I won't be surprised if anyone really hasn't tested it for IBCs and backyard purposes from a scientific point but I thought people may have anecdotal advice based on experience?

I currently have around 40 JP in my IBC (eaten a few and had some jumpers early on before I built my 'wall' of containment started with about 50) and that has been fine.. however now I have added 50L of k1 and extra air and RFF and mineralization tank so the bio filtration can handle much more, also I have all up about 3000L of water about 2000L sump and 1000L FT.. so I can have more fish without killing them but I was wondering what other factors to keep in mind as I am going to try and get new fingerlings this month.
I also want more fish since this year I have never had a nitrate nitrite reading and with the 10 towers and 3 flooded pipes on each wall plus my 3 IBC GBs I don't think I have had enough nutrients for everything (especially as the towers had about 70 strawberry plants in them) I could add seasol etc but would prefer to keep it mostly powered by the fish and fish feed they receive.

Yea Im not sure mate, there are DO requirements for fish species but yea like EB says sometimes-it depends, it depends on so many variables. 1 fish per 20L of fish tank water is a common 'safe' number used on this forum, I picked it up in the first year I became a member here but I dont know how it came about so in all honesty I cant really back it up with anything scientific. It most probably refers to fish welfare in an AP setting.

RAS books and documents would have some numbers you could work with but it would take into account a number of variables like DO, filtration, temp, water turn over etc etc. Only problem is that RAS change out water so the numbers might not be as good for AP?

Thanks again, yeah I guess even if I did look into RAS it still wouldn't nail down a specific number, like you pointed out RAS and AP have differences. Well my 50 fish seemed healthy this whole year so perhaps I just increase the number by a few without going nuts and see how it goes

The RFS that Paul from Earthern Group set up had a max of 50 Jade to 500 gram per IBC. He did not recommend stocking any more although the filtration system would handle more water through the system. Simple solution was to just add a third IBC if more fish are required.

WOuld be a simple solution and one that I would do if it wasn't for the fact that my system is crammed into a 12msq greenhouse with no where to expand unless I go up I already have to shuffle sideways in a lot of places to even move around and I even added my fingerling tank on top of my FT just because of space problems

Then I would suggest you stay with the 50 fish may save you some problems in the future.

you need to work out what level of DO can be achieved on your warmest day (warmest water temp) and then determine what biomass of JP that can support. That then is your "worst case scenario" for the functioning system.

Of course, if you stock to that level and the power goes out, you're going to have a lot of dead fish.

I will look into that... but as far as power goes I have battery backup with even more air

Yep, that's good, but aeration isn't going to stop nitrite build up if the power is out for a while, and it can be quite rapid in heavily stocked systems

Thats a good point chilli, having less fish per litre of water will lend a larger margin for error in a few instances like extreme weather, power outages etc

yes I definitely agree too.. although in my case I also have 12v pump by battery backup that moves some of the FT volume, less than the AC pump but enough I would imagine to reduce the risk of Nitrite build up.

Looks like you have made your decision no matter what people say Tom. Good luck and I would be interested in your results for this experiment.

You never know you may even reach Murrays dream number for a IBC .