Backyard Aquaponics
A place to discuss aquaponics

Two more deaths today with both of them on the small side. I had noticed a couple struggling with the upright swimming the day before so I guess that was them. The ammo is still high but the only thing saving them at the moment is the PH is down to 6.8
I have not given them any feed for the past couple of days and intend to hold them off till the weekend. If the ammo hasnt dropped by then I will go for a water change.

Temp - 27 deg
PH - 6.8
Ammo - 2+
Rites - 0.5
rates - 5

Did you salt the tank??

Yes I salted to 1ppt on Tuesday and had no fatalities on Wednesday.

You can salt alot lot higher than that. Salt is great for Barra, it acts like an instant tonic.

And the air supply...??? I hope you have heaps of air...you can never have too much with barra.

But question.....how old is your bio filter , to have ammonia that high for so long is a concern ? maybe it might have to be revamped ?? just trying to help...I would be worried at this stage, and floaters, means the fish have been dead for a while, so could contaminate the water. anouther concern ??

Hi Jessy
I do have plenty of air in the tank but I will add some more salt tonight to raise the level a bit more. The filter is a new build and I am guilty of adding the fish before it was cycled
I am going to do a partial water change this weekend if the ammo hasnt dropped and I may also follow Ivans sugestion of using some of the gravel and hydroton from my main system to help speed up the cycling process.

I would salt to 3ppt. From what I remember, 1ppt for mitigation of nitrite poisioning...
3ppt for stress and diseases... I did read that your barra were slightly stressed in earlier posts.

Thanks Ivan
I didnt get to do it tonight but I will in the morning.
There were no deaths today and more than half have lost the white stress stripe on their head. I gave them a small feed tonight and they seemed to respond to that well.

The Barra nursery is still ticking along with a total of 12 deaths recorded so far

I have not yet got the Ammo under control dispite a few water changes. I do now regret not cycling the system prior to getting the fingerlings but you live and learn.
The fish seem to have settled down as a whole and are more comfortable grouping centrally in the tank rather than crowding into the corners. Even though they have not been getting a lot of food there is still signs of growth with a couple of fish clearly twice the size of their brothers. I just hope this is not because they are eating their brothers

Barra are usually graded at around 80-100mm ... otherwise the bolters will eat their siblings..

Have you tried getting some cycled gravel from the other system to "seed" your nursery filter??
I think worm castings help as well...

Also... have lots of aeration... I was not aerating my second system with airstones so the ammonia stayed
at 4 for a while... Put airstones yesterday night... tonight the ammonia is 1....

I recalled that it was Rupe that mentioned somewhere in this forum that oxygen is necessary for ammonia
conversion to nitrite, hence put in the airstones... and well it worked...

It most certainly is... and with the extra oxygen demand for processing your increasing feed level, fish growth, increased metabolism with warmer water temps... you'll have less oxygen available for an increasing number of bacteria... something has to reach a limit... and it's probably the bacteria that will do so first...

Thanks for the info
I have introduced some of the gravel & Hydrton from my main system into the nursery filter so I hope that will bring things along. On the air supply I have one of the twin outlet BYAP units so I would like to think that is enough air but if people think there should be more please let me know.
I tested the water again last night and the Ammo is around 4 , the Rites at 1 and the rates at 5. Temp 28

The little guys are hungry as they now congregate at the end of the tank where I am standing when I lift the covers off. It is hard not to feed them but I am going to hold off any food for a week to see if I cany get the water quality under some sort of control.

On the grading issue I think I will have to look at making a divider of some description to split the tank in two sections

Death count 13 out of 58

Definitely stop feeding at Ammonia level of 4...

Well I am not sure whether you have enough air, as I never really worked out the "formula"... But I think you can never supply them with too much air... Someone with more experience might be able to advise...

IMO, if your ammonia is not dropping without you feeding, it might be worth trying to add more air... You can buy a cheap AC air pump with airstones and give it a go...

I have a couple of the cheap battery ones that I use for transporting the fish so I will set them up tonight as well to see if the extra air is the answer.

Well a bit of an update. The death count now stands at 17 from 58 and I still cannot get the Ammo to drop.
I am at a complete loss as to what is going on in this tank.
I have doubled the air supply , I did a 50% water change, I have salted to 3ppt, I have stripped down my filter and removed all of the off cuts of poly pipe and replaced with hydroton from my main system. I have a venturi from the pump to the filter so it is bubbling up through the hydroton prior to flowing back into the FT.
My water readings tonight
PH 6.8
Ammo 4
Rites 5
Rates 20

WTF am I doing wrong here