Backyard Aquaponics
A place to discuss aquaponics

Hello aquaponics enthudiasts,
We have set up our system only in January this year (2012) and put 18 silver perch and 10 yabbies into the pond.
See pictures at
gabi-glaezer.blogspot.com
The fish seem to be happy and swimming around, coming to the edge when it is feeding time etc.
We can see the yabbies at night when we use a torch but from the 10 yabbies we have put in approx 3 weeks ago 5 have died already.
There was a feir amount of sun on the pond, which is why we have put up the shade sail and we had lots of long green algae's growing which are less now with the shade sail but there are still a few.
We feed the yabbies carrot and lettuce and they love cucumber and come out at night to have a feed. When we bought the yabbies someone told us they need to have riversand on the bottom because some algaes grow on the yabbies body and so they wiggle through the sand to shed them off. Anyone heard of this? We have probably put in 20 kilos of riversand (2 large buckets full) maybe that is not enough. We put PVC pipe into the bottom so the yabbies have somewhere to hide. Does anyone have an idea why the yabbis are dying? Any help is appreciated.
Thanks in advance
Gabi from Gosnells

if the water is clear, the yabbies will tend to fight and pretty much kill each other off. if the water's not clear, you probably can have more yabbies in the pond. There's a density ratio floating around the forum regarding how many yabbies per sqm of pond/tank space you should have.

Good luck!

You only want about 7-10 per square metre floor space with lots of hides. Yabbies are terratorial and agressive and dont live well in a habitat where they cannot burrow. I try to stick to all females as they cohabitate better or you can use elastic bands to tie the claws to prevent canabalism.

The whole river sand thing is a crock sorry. Not a good idea to have sand in your AP system either.

The other thing is yabbies will eat fish and the fish will eat the yabbies.

What does the remains of the dead yabbies look like? have they been mutilated or simply just dead carcasses? Do you know what your water parameters are because you will need to rule out any issues with the water itself. They dont fair too well in water with a PH lower than 7 and will start dieing around 6-ish.

How mach filtration do you have?

Would your system be fully cycled Gabi? When did the last one die?

+1 on them being territorial -
if they're dying when molting you can add iodide (used in marine aquariums) at half the recommended dosage for marine aquarium treatments..
i found this info on a crayfish forum, and since i started, i'm seeing more molts, and no dead crayfish..

Thanks for all your information and inputs.
We bought 10 yabbies about 3 weeks ago. One died that same day in the evening (maybe due to transport or so...). Then they looked okay for a few days until we found a dead one some days later. No signs of being eaten or attacked just dead. A few days after that we found another dead one and so it went on.
We thought maybe it is the algaes (too many) so then we put the shade sail up.
The dead bodies are not looking as if something has eaten or mutilated them.

Yes the sand... we didn't know but where we bought them the guys who got some before us said they need the riversand. So we have one little "sandy beach area" furtherrest away from the pump. They also told us how to determine the male and female so we got something like 3 male and 7 female. Brendan my partner wanted to breed them

I don't think I want to band up their claws.. feels a bit like torture to me and the fish swim right near them without fear. The yabbies are actually trying to catch the fish but the Silver perch are very fast and swim away. Due to the fact that the Perch swim so close to the yabbies I don't think there is a great chance of them yabbies eating the fish, and the pond is large enough for the fish to escape.
We have the pump running 24/7 at the moment and the pond is approx 2000 liter I think the pump is for 4000 liter so there should be enough water movement.
I will check the PH level or get Brendan to check it because he is actually the fish fanatic, I am more the gardener but I am the PC user (he hates typing) so I need to do the asking in the forum.

Filtration: we have the one growbed (that is considered filter right) and I would not like to put any chemicals into the water just yet.
Also we have spray painted the pvc pipes with some black enamel spraypaint from Bunnings (only the outside).
Brendan was wondering the other day if that might be the problem. If the yabbies eat the algaes on their pipes and the paint is toxic... or say not healthy.

I was thinking I could make a little hiding place out of clay/pottery for them Bisque fired that should work okay.

Thanks again for any suggestions... maybe it is just the hot weather we have lately.
Cheers from Gabi

Ive been doing this for many years and have trialed so many ways to cohabitiate yabbies and fish and unfortunately it just doesnt work very well for a thousand reasons. You will get some through so Im not putting it down but just keep a very close eye on things is all Id like to say.



Yes they will, Ive witnessed this in my own system many times.



you will have an extremely hard time breeding them in with fish, babies yabbies in a solid bottom pond or tank have about a 5% survival rate, the yabbies will eat them and the fish will eat them.



Enamel paint may contain a wide variety of solvents. Automotive enamel paint typically contains larger quantities and more dangerous versions of these compounds than house paint, and outdoor house paint presents a more toxic profile than indoor house paint.

Typical toxic solvents used in enamel paint and other household chemicals include toluene, also known as methylbenzene; benzene; ethylbenzene; and xylenes, according to the Ohio Bureau of Environmental Health. Mineral spirits (also known as white spirit or Stoddard solvent) may occur in paint and can also have neurotoxic effects. Acetone, also used as an enamel paint solvent, has a much lower toxicity.



yabbies can tollerate temps of near freezing to near 40 deg.

hope this helps but Id be removing those pipes and checking your parameters

yep get that painted PVC out of there!
If you want I can give you a metre length of 32mm black poly pipe which is much safer than black paint.
I work in Gosnells so it's closeby