Backyard Aquaponics
A place to discuss aquaponics

Hi all
I had a brief chat to a guy (Neil) who trained as a vet and went on to specialise in fish and fish diseases. He recently wrote a PHD on a barramundi parisite which he discovered. He's got alot of experience with commercial aquaculture and is currently working in buisiness to to establish a commercial aquaponic farm north of Adelaide. When I told him about my system and the 3 different fish species I had together, he went onto warn me about the perils of keeping more than one species in the same system. I explained that I was planning to have a winter crop (trout) and a summer crop (silver perch or catfish). The concern is not that they are in the tank together but rather that they share the same biofilter. He described that in a river you have many different species together, but at extreemly low stocking densities and water is constantly being replaced. Things work differently in a reticulating system with a high stocking density. Different fish species have different gut flora, and these are going to be in relatively high concentrations in a reticulating system. But while one species will cope with its own particular gut flora, a different species wont and could die or at the very least wont flourish. He attributes this as the main reason why some aquaculture ventures have failed.

I know that there are plenty of us here that keep more than one species together, Neil suggests that you might want to reconsider this. He says you might get away with it at low densities, but at high stocking you'll probably run into trouble. On a positive note he said that your growth rates and fish production/harvest will be greater if you keep just one species for the whole year, compared with two different species as I had planned (a winter fish and a summer fish).

I didn't get any technical data or references but I'll ask next time I see him. I have invited Neil to come to an SA AP meet but am waiting for his reply. Something to think about + discuss, and i could perhaps forward any questions to him. Has anyone else got any info about this?

Something that hasn't been talked about here before KE14, should spark a lively debate

Some of us have a mixture of SP, JP and goldies and I intended having barra and SP in the same system (segregated of course), must do some research

lol just dont keep trout n goldies 2getha, just ask my remaining goldies without tails

That's a bugger if it is accurate. I have every intention of running multiple tanks with different specises - but all linked into the same biofilters (ie the grow-beds). Because the sump & pumps will be shared, I have no other choice. Will still run with it and see how it all goes.

Yeah, I am very keen on winter trout summer barra. The growth rates of our current small batch of trout is proiving the possibility of growing them out in 5 months from advanced fingerlings

Yea i am running trout and silvers looks like the trout will grow out by the hot weather

Whats your water temp F&F?

Two days ago 18 now 16

excelent! oh BTW would that be at the end of the day?
Would be interesting to see the variation morning to evening!
Those trout big enough to eat yet?

Interesting info KE, thanks for posting, gives us something to watch out for!



Thank goodness you wrote it like that! i would have died if you wrote "he is the first person in australia with a PhD in barra parasites"

I have a perment thermometer in there depends on the day normally 2 deg diff night and morning

awesome!
Plenty of waterbody and your tanks and sump are in the ground aren't they?

Yep

Mmm...
makes me think more about the ground temp being a major influence
in the stability of temp.

What are your tanks made of FF??
I have been thinking of putting a few fibreglass tanks into the ground but am unsure if movement in the soil would crack them?? I guess they do it with swimming pools so it should be ok. I was talking to a Barra farmer recently and he raised his tanks in his shed as he recons there was a 6c temp difference between the top of the shed and the bottom!!