Backyard Aquaponics
A place to discuss aquaponics

there would be no spraying by Forest but any neighbours?

I'm not sure about spraying. Our next door neighbours have been away. We did have a neighbourhood kid come in to look at the fish yesterday, but I doubt he'd do anything. We never spray and only use organic compounds here.

we've got some salt ready, it's already outside.

Sorry Forest.... forgot your pedigree .... ..... no offence meant

I've googled this and found some info about dissolved oxygen. We have had a couple green floating blooms the past couple of days. They dislodged from the side of the tank. i'm wondering now if this has caused the water to deplete its oxygen. That, along with the no pumping at night night have caused this? maybe?

none taken, rupert.

Forest - when the pumps are off at night have you been providing any aeration?

Did you salt the fish after you purchased them, I can't remember?

If they don't perk up quickly with the air being provided, given that PH, ammonia, nitrite and nitrate are all good, I would guess disease and accordingly would provide 3ppt salt. To reduce the amount of salt required, given that your fish are still quite small I would reduce the amount of water in the system.

Forest - algae will certainly use up oxygen.

when the pump is off at night, so are the two aerators. so no oxygen is going in at all at night.

the tank was dosed up with salt about two weeks after we got the fish.

what sort of diseases do fish get? what are you thinking of VB?

and .... (correct me if I'm wrong VB).... doesn't ammonia go up overnight also..... compound that with no pumping/conversion of ammonia/renoval of nitrates..... even further lowering of DO..... sound possible VB??

Edited:
Having said that though.... there doesn't appear to have been any ammonia spike........

Do you think the algae alone would be enought to cause the problem VB

Either way the chances of stress applied to fish would be magnified....

Stressed fish get sick easier....

i've checked out the dead fish. they all look perfect. Nothing around the gills, no discolouring. Eight dead now.

Sounds like DO problem the more that is said about it. Pump as much air as you can into the system. Have the pump making as much of a waterfall as you can and also have whatever air pump/s you have going as hard as they will.

If they don't perk up though, then it is possible that disease has hit because of the conditions. If they haven't picked up by the end of the day I'd salt in the hope that it may help.

Are they looking any better forest?

there are no further fatalities. We've let out some water and added a few hundred litres of fresh rainwater via a spray hose over the surface of the tank.

Given the levels that the tests showed, a water change should not have been necessary.

Good to hear that they seem to be picking up. Keep that aeration up 24hrs a day 7 days a week, it is essential for fish survival.

Poor Forest.

I hope you don't lose any more.

I agree it sounds like DO. My goldies were behaving like that when I topped their tank up. Usualy their filters are like a waterfall but when I filled it there was no splashing and next morning they looked miserable. I put the airstones and pump on from another tank and they perked up, and in a few hours were back to normal, but goldies are hardie little buggers!

I think your silvers are a bit less tolerant. Hopefully aeration has solved the problem and soon they'll be happy fish again.