Backyard Aquaponics
A place to discuss aquaponics

well it looks like its not the food

so far the silvers in the black system ( no deaths yet - ever , fingers crossed ) eat it as soon as it hits the water , its a few degrees warmer with the added benefit that the fish taste like bitumen because of the bitumous sealer

woke up thismorning and found ALL the large silvers in the other system dead , plus half of the fingerlings . toxic buildup or something I suppose and it took a while for it to it the big ones . theres 30 - 40 little ones still hanging on , I'll watch them today and not feed anymore . threw in a couple broccoli leaves to see if they munch on those once they sink

the salt seems to have done nothing to stop them dying , so I figure its not a disease , the food doesnt kill the others so I figure its not the food . must be a buildup of some chemical somehow . nothing is leaching into the system . there's a fair bit of dolomite thats dissolving exceedingly slowly . about two weeks ago I added a sprinkle of Iron sulphate in each growbed . cant figure it out

water tests are fine , nitrite is .25 , ammo 0 , pH 7.2 or so

slight dip in temperature but not much , not enough to kill them for sure . Changing the water from now on till the end of next month ( slowly - I want to keep the nutrients for the plants that are going mental ) till the trout arrive

this system has just been designated the Trout/Barra system , no more silvers allowed ..

filletted the 7 biggest ones , half male & half female with a Huge amount of eggs in them

How much iron sulphate and why?

How much dolomite lime, when and why?

I am curious as to what problems or deficinecies there might have been to explain adding a cocktail of additives.
I think I remember you added a large amount of eco rose at some point a while back.

Good questions Faye

can't really remember , it was a while ago
dolomite about 2 months ago maybe 3 , 10 kg at the most probably less . buffering or something I suppose . its not even all dissolved yet still

Iron sulphate to fix a slight oncoming iron deficiency , sprinkled into the growbeds under the water pipes to help disperse . added about 100 grams over the course of a few weeks . again that was a while ago

the ecorose was ages ago , that was to bring up my pH from below 6 , maybe 3 or 4 months ago ?

Im pretty sure its not any of those as I added the same percentages of the same stuff to the other system at the same time - those fish are fine and eating great

the only difference is -2 degrees cooler in this system always.
found one week old dead gecko floating in the top tank ( I dont suppose gecko's are poisonous to silver perch )

its not fungicide from any of the seeds Ive been planting ( most are saved seeds anyway ) - same seeds planted in both systems

I also just did a big salt boost , up to 3ppt+ in one hit , in the hope that it was a disease or something and that would stop it

the big silvers all died in one big hit overnight , the small ones are still swimming around in circles / upsidedown then dropping dead. some seem to get better for a while

its possible that the extra rain topped the tanks up so much that the air was off those two exact tanks all night , but I did check it & I really doubt that was it , having gone through and checked all the air pipes today

theres a fair few tiny dead snails in one tank ( 2 - 3mm ), theres no ammonia spike from them having died , but maybe they release a toxin or something

once all the fish are dead tomorrow I'll just get a broom and scrub the hell out of all 5 tanks , then keep doing that every few days till the growbeds have cleaned up the water

How big, and how old were the Silvers???

It's very late in the year for Silvers to be in roe...

25 - 30cm

got them two novembers ago when OBO did a big fish trip

looking at the air lines , its possible that the tank with the big ones just fills up too much and doesnt get any air after the last drain , I'll have to check that tonight at 1am to see if its got bubbles , maybe they all died in one hit from no oxygen and the smaller ones are just still dying from whatever it was they have been dying from for weeks

the big ones did look exactly how a tank of oxygen starved dead fish look ...

BUT , the little ones are all of a sudden swimming funny then dropping dead as of last night / thismorning - usually they just die ( one every few days since I got them from golden ponds ) I could put those original deaths down to either starvation ( a few were ) or the food not agreeing with them , but these new deaths today look liek a different cause

only lost 14 of the "big" ones ( theyre still babies compared to last seasons trout ) so I dont really mind taking that as a forced fish dinner , plus theres another 50 - 70 in the other system the same size ( but they taste like bitumen )
Im not even so bothered about the fingerlings - that was only 50 bucks , Im more worried that it IS something toxic in the water incase the same thing happens to the trout as soon as I get them

I suppose a good scrub clean , filter through the beds till clear , then slow full water change over the next month is my only option

The deaths of the bigger fish overnight definitely sound like lack of oxygen...

I'm a bit concerned as to your remarks... that the other ones taste like "bitumen".... what did you paint the tank with...

Are your tanks seperated... or joined...

Thats a completely seperate system

they taste like bitumin cause the tank is sealed with Sikatite BE , a potable water grade bitumous sealer , C1's suggestion

the water tasted like bitumin for a month or so , but the fish still retain the flavour almost 2 years later . I'll purge them if they ever get big enough to eat

the small silvers that are still dying are swimming around sideways ,upside down etc, some just sit upside down on the bottom but when I go to scoop them out they shoot off normally , then start swimming wierd again

the ones that are swimming normally ( most of the remaining 40 ) are all over the place at different depths - usually these silvers all swim at the same level / depth but not today . as I watch some of them go from swimming normally to wierd , then sit on the bottom upside down . looks like a few might pull through theyre not showing any strange behaviour apart from swimming slow and not being hungry . although one attacked the net and wouldnt let go

the chickens had an absolute feast today

Hi Boris, I seem to recall that you have used some batu wood to make tank covers.

I too have used batu wood to make tank covers and it seems coincidental but the goldfishes and koi seems to have started dying as I was completing the covers for the fish tank. I was suspecting that it was high temperatures at that time, because the water was getting to 34degC, but I have recently put a few goldfishes in when temperatures were a bit lower and they also died after a few days... Only yabbies seem to survive in that system... Some pieces of wood are constantly wet because the air stones bubble up the water to the wood, and of course the water drips back down from the wood to the tank...

I am not saying that it is definitely the batu wood but I am sharing my suspicion...

I believe batu wood is imported into Australia and are fumigated with Methyl Bromide when it reaches quarantine...

I will be investigating further and possibly throw 1-2 trouts into the tank during winter... If they die and the water parameters are good, then I think it is the batu wood...

shouldnt be the batu - Ive successfully grown out 2 lots of trout in the system

there is one small piece that gets constantly wet, but its been like that from the start

just ate the big silvers for dinner . no wierd flavours and no sudden stomach pains .
I think I prefer trout - silvers have got too many bones and theyre all in the wrong places .
I suppose if they were a bit biger I could have filleted them though

a few more dead fingerlings , about 35 left now . we'll see how they go through the night

I've checked and re-organised the air piping , its still possible that the big ones died from lack of oxygen ( pretty sure thats it ), but the small ones dying is a mystery still

Iv may be on to something as your fish deaths have occurred after the recent rain events so there could be a good chance that something has washed into your tanks. A couple of years ago I lost a few baby silvers after the first autumn rains when water ran off the corrugated Iron roof and into the tank.
Are you just running an aerator during the night and not the pumps?
Do you have a refractometer?? Or are you just estimating your salt levels?? Perhaps your levels are much higher than you think??

the celery tends to taste salty for a while then stop - that means its sucked up all the salt & theres none left

though my other plants arent showing any problems so Im assuming the salt isnt that high . the highest it can possibly be is 7ppt as thats all Ive added ( 4ppt about 5 - 6 months ago and 3ppt a few days ago )

the big lot of deaths ocurred thismorning ( after 1am & before 10am ) , no rain since tuesday but it is possible something had leached in from that . the whole system is covered - doors on the front , colourbond fence all around , growbeds over the top

its as if there's something in the water that started killing the fingerlings the day they went in , then built up to the point that its bumped off all the big ones in one hit and killed more and more fingerlings as it increases ( although at this point I really think the big ones died from asphyxiaton )

Ive had a really good look through the growbeds , and all the tanks , theres NOTHING visible , I kow theres no metal that could be rusting into the water apart from :
-inside the 2 pumps , but they still work

-tiny exposed pieces that are the pins that hold the little valve at the bottom of the IBCs together , theyre covered well with silicon though

-metal cage holding top IBC half growbed above top tank - its not at all rusted though

if Troutmans right its runoff from the patio roof getting into one of the small growbeds , sittign there for 4 days then filtering through . I would have thought the effects would appear straight away from that

I was losing one small one every day or two ( ever since I put them in ) , lost 3 in one day so I dumped 3ppt salt spread throughout all 5 tanks on thursday , saturday morning lots of deaths - normal natural lake salt that Ive always used and I added the same percentage to the other system with no ill effects ) , is it possible the salt reacted with some other unknown chemical already in the system to become something toxic to fish ?

3 more dead just now , 29 remaining

Yep - just an aerator at night and not the pumps , last cycle is 15 minutes on at 11.00 , takes a good half hour to drain atleast . first cycle next day is at 7.00

hmmm , duckpond lost a huge amount of fish last time he dumped salt in ....