Backyard Aquaponics
A place to discuss aquaponics

Help please,

On Thus I put 40 Barra (size 10 - 15 cms) into my BYHP and by Sun they started dying.

My system is 1 yr old. I have had 1 successful harvest of Barra and 1 of Trout.

I harvested the trout about 3 weeks ago and then left the system to filter for 1 week before putting the Barra in.

The Barra were not eating and the ones left are still not eating.

Water temp when I put them in was 16, yesterday it got to 24. I have been putting a heater on at night but it does not do much.
I am in the Manduah WA area.

All the water tests are perfect.

I have two air outlets on my air machine. Water is clear.
The BArra seem to be docile and the ones that die were hanging around at the top. I was putting a pool blanket on half of the tack to warm the water. The tack is 1000 lt and I have two grow beds and all plants are great.
Any ideas?

Yesterday in desparationg I took some water out and then put some rain water in. No more have died for 12 hours. is it air, water, or temp do you think?
I am puzzeled.

thks,

Linda

I think it could be a combination of a few things Temp / Transport shock / 02
What was the water Temp they came from ?
how many have you lost ?
How much salt have you got in the tank (Barra love salt)
They wont feed very much at all until water Temp is consistently above 20c

I would suspect that it has something to do with the transportation and temperature shock. From previous experience and reading others experience, barra does take a while sometime to get use to their new environment.

For a 1000L tank outdoor, you would probably need at least 600W of heating. What size heater do you have? The heater should have a thermostat such that it maintains the temperature of the tank throughout the day and night, rather than only turning them on at night. In other words, during the day, if it is a warm day, the heater will operate at a minimum. If not, the big temperature flunctuations from the day and night (when the heater comes on) will stress the fish out more.

Barra would survive with water consistently above 20degC. And I think they will only start eating at >24degC and after they are comfortable with their new environment. So don't keep popping your head over the tank. Covering the whole tank (black out) would help.

And yes do salt your tank to about 3ppt (1ppt is 1kg per 1000L of water), this helps prevent opportunistic infections/diseases infecting them while they are stressed.

Thanks for your help.

I have put in some salt before with the trout and assume it's still there. I have lost about 20 of the 40. Today they (what is left) seem to be OK .

Temp when I got them from Golden Pond was 16 and now the water is between 18 and 22. The heater I have is small and not changing the temp much.

I now have the tank covered with a shade cloth (and I'll try to stop popping my head in to check).

How many fish of that size do you think is OK for 1000lt and 2 grow beds?

SOunds like its temp and stress from being moved.

I'll cross fingers that the rest will be OK.

Well if it is 2x 500L growbeds and in an established mature system, you can have about 40-50 fishes. Just in case you are thinking about adding more fishes later, just make sure that they are about the same size, otherwise the smaller ones may disappear. But 20 fishes should be able to support good plant growth.

Sad to say but from experience, GP don't provide good conditions for their fishes. I would consider buying yourself some good heaters. If temperatures get colder over the next few weeks, you might struggle again to keep them alive. And putting the shadecloth will stop direct sunlight from heating up the water (I know I said cover it up!). But that is these are the issues when you try to defy nature. If you are not prepared to pay for heating costs, you should consider only putting barra in the tank when water temperatures are consistently over 20degC.

WHere else besides GP can I buy Barra?

Tks,

Linda

Challenger TAFE Fremantle have barramundi at $2-00 each 10cm (100mm).
Just a warning if you are adding them in with larger fish, as barramundi will eat their own. I am also wondering if the fish you got already had lost many scales in transport?