Backyard Aquaponics
A place to discuss aquaponics

Definately wont kill them. I reguarly move fish from a freshwater flow thru tanks to recirc tanks with Nitrate present and have never had an issue.

There may be anaerobic bacteria present if there is little pO2 but these would not have caused the anaerobic conditions. They don't metabolise O2.

I am not sure most of us have the money for an O2 tester. Anaerobic bacteria (spelling) may not consume O2 but most of their end products have an affinity for O2.

I agree with Troutman. This season the trout were placed in my system with 400-500ppm of nitrates and the fish were smashing food by the next morning.

Is it possible that the esky or container that you and Gran picked the fish up in had contaminants of some kind? Maybe you had cleaned them with a washing liquid or something? Im just spit balling here.

If you mean Po2, I fail to see the correlation with anaerobic bacteria. Po2 means partial pressure of oxygen and for divers an important issue. Unless we are talking about scuba diving bacteria?

I agree with Sleepe's statement, the second part at least. For the first, I think it is possible to do chemical testing for saturated oxygen? (Me just another s?&4cker trying to get by).

I thought oxygen saturation correlated with po2 of a solution. That's what you measure in blood anyway.

Maybe google around a bit?

As I mentioned, those solids were removed about a month ago, so I don't think its likely to be anything like that. Plus the fish showed no signs of oxygen deprivation.





This is good to know, cheers fellas.



Mine were delivered by the supplier to the pond, so it seems unlikely, but all metaphorical spitballs are welcome.

Have your neighbors or the council been spraying lately?

I doubt it would have been the roundup! Just ask Monsanto, you can bathe in round up! Well at least your crops can!

Seriously, might it have been temp shock? I imagine the large pond would have been on average cooler than a smaller transport esky that would have been more or less equal to daytime am isn't temp.

Just a thought. You know how when you bring a goldfish home from the pet shop you need to equilibrate it in its new tank b4 letting it out?

Ambient temp that is bloody autocorrect

if it was DO then they would all have flared gills and the gills would be a dull red with a white gloss. By flared gills i mean they look like they all died of shock horror with their operculum forced out wide open and held there by rigormortis.

Add an airstone or two and the remaining fish should perk right up within about 30minutes.. if they dont its not DO. Cheapest DO meters are like $200, we use oxygaurd polaris's at work, they are 1200 each but are priceless.

Also if you have incoming fresh water higher in DO from a growbed or something then the majority of the morts will be right underneath that and the remaining fish will be sitting hard against it with their nose right in the flow. Should be really easy to spot, the fish know where DO is if its getting low.

Sometimes things like this just go unexplained, whether it be ph shock, temp shock, ammonia, chlorine, sulphur, carbon dioxide or 100 others you will never narrow it down without rigourous testing, but your often too late to catch it in the act.