Backyard Aquaponics
A place to discuss aquaponics

Hi All
I have a mature system approx 18mnths old it is a BYAP entertainer. We pulled trout out in september last year and put 50 silver perch fingerlings in in October (avg 5cm). All has been going fine for last 9 months. Today my wife found a floater which was small (not even 10cm) so we assumed runt die off. Had been awhile since i had pulled some out to get a gauge on size so did a sweep with my net and ended up pulling up another 13 fish from the bottom of my tank before cold and depression forced me inside. I am hoping that this is all that has died.

Checked the water vitals and all looked good.
pH 7
nitrates 0
nitrites 0
ammonia 0.5ppm

I am assuming the ammonia is beginning to rise due to dead fish decomposition.

We run a grow bed flood for 15 minutes every hour 24/7 and have a 2 air stone system bubbling away all the time.

The dead fish ranged in size from 10cm to 20-25cm in length. Most looked fine, a few had a much lighter dorsal surface that ran from the tip of the mouth along the full length of the fish, not sure if this indicative of disease.

I am going to stop feeding for awhile as a precaution.

Would salting be beneficial even without a nitrite spike?

Are there any other recommendation?

Cheers in advance
Rob

(If you want to see the system and get an idea of how it was set up i have pics and details in my system thread)

No idea what's causing the deaths rob, what's water temp been like? Definitely salt to 2 ppt just invade you get a nitrite spike now ammo is up, also incase of disease

Thanks freo.
With ppt is that parts per thousand or trillion. i.e. 3g/L or 3ug/L
Cheers
Rob

The easiest way to think of it is 1kg of salt in 1000L = 1ppt

Maybe water temp , can get pretty cool in fruit growing areas.

Cheers

Checked water temp this morning and it is at 10oC. From my reading silvers are meant to be pretty cold tolerant, they just don't grow too much.
There were no more floater this morning.
Will pick up some salt this afternoon and dose this evening

How old is your test kit? Could it be that it is no longer accurate?

Checked the test kit and reagents are 2 years old. Websites I have checked suggest min of 3 year shelf life for reagents. Have not seen any more floaters so will just watch and see.

I would take the water to a aq shop to get tested just incase

You may be hitting the bottom end of their tolerance Rob, 10C is really getting down there. Have you found not much response at all to feed? Mine are sitting at 16C and only feed every 2 to 3 days. If there is no other physical signs I would go with that. Are you feeding much at all? If not, then nitrogen and oxygen are really not going to be an issue at that temperature. Perhaps they are starving or just a tad cold...

Whereabouts are you located Earthen Group... 16 degrees for this time of year isn't bad..

We haven't been feeding much but i have a sneaky suspicion our 2 year old has been feeding the fishies without our knowledge leading to an excess of feed in the tank.
Talked to the guys at BYAP over the weekend and they recommended constant pumping for awhile. Water quality has improved and no more floaters so hopefully we are all ok.
In all i think we lost about half of our fish Fingers crossed we will have no more issues.