Backyard Aquaponics
A place to discuss aquaponics

Can anyone tell me what this disease is? Looks like puss in the eyes.. all barras are like that for a week now and have pretty much given up hope on them. They are currently in a very salty water..gave them high concentrated salt baths as well.

Nitrites were very high for while.. it still is but just reduced a slight bit..

Water temp staying at around 20 when I checked in the morning (with the help of heaters).

Any help would be appreciated.

20 is getting near to the bottom of the range for Barra... especially if your tank is dropping down to, or below 18 at any stage overnight.... and you might as well pull the Barra out... before they float...

Think I'll have to just take them all out. They all appear to be infected somehow. 20 is the lowest it gets during the night these days. It's states a bit more warmer in the day but it's still probably not enough.

I believe I had one barra that had both its eyes like that before. Needless to say that it did not make it. I would immediately isolate all remaining healthy barra from those that are infected.

Try to see if you can raise the water temperature higher (about 22-23degC) especially during the night. Turn off the cycling to the growbeds in the night about an hour after sun-down. And use a timer to turn it back once the sun has been up for an hour or so.

Low temperature at the limit can stress fishes out, and stressed fishes are more easily affected by infections and diseases.

How high is high nitrites?
I would blame that first before the temp...

nitrites are around 2 ppm now..

I used to turn the pump off during the night to keep the temperature for around 5 hours and I have a theory that bacteria died when I started doing that.. and thats probably why the nitrites are not getting converted properly. Now i have them running every hour for about 20 mins..

If your nitrities are 2... then you need to salt to 1ppt..

the tank is already salted to atleast 6ppm for the last 4-5 days.. it used to be 5ppm, but came down to 2ppm

Ok.. good..

Lost about 12 barras to this.. and have 9 left..

They seem to be stable now..all infections gone..clear eyes and clear scales(apart from few with burn marks from heater).

They started eating happily now too..

Lesson learnt:
1) Barra really do need to be in higher temp water.. keeping them at bare minimum for extended periods is not good.

2) Turning pumbs off for extended periods of time(from 6pm to 6am) might might kill off a lot of beneficial bacteria in GBs regarding the cycling useless (although not too sure about this point..someone pls confirm)

3) Need to control feeding Barra as they like to eat a lot but when it comes out the other end, it can cause spikes in amonia->nitrites especially in new systems.

Turning your pump to the grow bed(s) off overnight wont kill off the bacteria to any significant extent...