Backyard Aquaponics
A place to discuss aquaponics

I have lost 4 of my Barra in about 5 days. Varying in size from 80mm to 200mm. No signs of cannibalism or other body damage or fungus.

Internal gills are bright red but I assume this is natural for oxygen exchange.

Ammonia 0.25 ppm
Nitrite 0ppm
Nitrate 100ppm
PH 7.4
Water temp 25 deg C
Water crystal clear

I am considering a 50% water change and salting at 1kg per 1,000 litres.

I would appreciate your thoughts and suggestions.

Cheers Wal

ther last line of your signature certinaly rings true !
salting is always a good idea straight up.... ammo isnt anything ot worry about
. . . .hmmmm

any pics of the fish??

Definitely add some salt... only other thing I can think of is aeration.

If you are running flood and drain via timer, switch to manual (ie constant flooding) for a few days... this will help clear up the ammonia and increase aeration.

Make sure there is no uneaten food on the bottom of the tank or anything dead. (If so remove it) +1 for salt and aeration.

OK, so I have removed 50% of the water and replenished and dosed with salt... I will keep you posted as to the happenings now on.

What airation method you using Wal.

Each tanks has a 1m long spray bar with 2mm diameter holes every 20mm along its length. This is suspended 150mm above the surface and directs sprays at the water surface causing turbulence.

Each tank also has a 19mm diameter pipe recirculating into the tank.

Each tank also has two 100mm long air stones. Currently running three in each tank until I know what's going on.

Each tank has a grow bed return from the bell siphon.

To be honest I think I have heaps of air and water circulation.

Thoughts?

Wal, is there any plants dropping stuff into the system? This has caused problems before, from gum trees I think Or the other one could be poison spray.... Any more deaths since water change?

Do you have any pics of the casualties Wal.

What have the tank temps been over the last week??

Yep, certainly no problem with aeration.....

OK folks I have added a couple of pics of the croaked fish. I see on one that he has a brown mark on his cheek and his eye is blood shot. The other one does not display these characteristics.

These two were dead today but I suppose the could have been crook prior to me salting, etc.

Any clues?