Backyard Aquaponics
A place to discuss aquaponics

No egg on face just a true gentlman...
les that is the way to do it, and a variation would be inline with mortalaties.

When I got my 200 silvers, I just tipped the whole bag straight in. Not saying or reccomending to do this, just that none of mine died. However, 2 did die when ammonia went thru the roof..... silver perch are tough little buggers.

not when you poke a knife in them, for a bit of surgery before the hot plate. heheh

Well the guy i worked with ordered in 10,000 silver perch (again don't quote me) and he said he spent over $2000 in trying to keep them alive. He was trialling a new fish distributor, but i dont think he will go with him again

He used ozone gens, UV sterilizers, Reverse osmosis units and many hours in trying to keep them alive. But once they decreased in numbers all the methods used started to kick in. The tank wasn't over stocked and it was aerated and clean water. He still has to best 60 of them left all really good size, about 40-50cm in size.

...and we go into HSM at the loss of more than one

Percentage wise it is a big loss, welcome Nicholas

Yeah i cannot stand the loss of a single fish either but he was really angry over that (as you would be), but i guess thats business.

Well i hope our setup goes well we might be getting either silver perch, Murray cod or trout.

or option 4: SP, Murray Cod....AND...trout

lol there is that but Murray cods might just be brood stock and the trout the human food actually your onto something there!

OH year sorry just realized what SP was... silver perch lol

Dad acclimatised them to temperature for 20-30 minutes but after that he emptied the bag into the tank. So it could have been a pH disruption. Bear in mind, the fish didn't all die at once, some took nearly a week (and 20 out of 100 survived).

It was a costly mistake, both financially and emotionally.

NicholasC, are you serious that your friend bought 10,000 fish and only 60 survived? That's, like, a $10,000 loss (unless he went through a seriously cheap fish breeder).

That's good he got the temp right, the ph is probably not necessary, sometimes I overkill on these things - still something did the dirty deed and its annoying not knowing the cause (apart from being costly)

Yes, I don't know how the remaining 20 are going - he's been away for a few days so they've been on auto-feed. When he returns I'll find out what's happening. Fingers crossed they haven't all died...

Okay, an update. Problem still not sorted out. Of the remaining 20, 17 more died. That's a 97% death rate making it extremely distressing.

pH was tested with the high-range kit and appeared to be 7.8

Ammonia levels have gone up to about 1ppm

Since the remaining 17 died, Dad has bought another 8 silver perch and 6 catfish (I think that's the numbers). He believes all the perch have died after a couple of days, but he thinks the catfish are still alive and look happy.

What is going on?!?!

Temperatures here have been UNBELIEVABLY cold; I mean, the water is almost painfully cold to touch. Being inside the shed, it doesn't get much of a chance to warm up during the day and then night temperatures are getting down to almost zero. I wonder if this means the system will be better suited to coldwater fish like trout during winter, and then perch or even barramundi in the summer?

Suspicions:

- high pH makes perch hypersensitive to ammonia
- cold temperature stresses perch
- temperature stress causes fish to stop eating so they starve

On the plus side, the plants seem to be happy. Those are going to be some of the most expensive veggies Dad's ever had...

Definitely...
Probably....
Maybe....

And that's about average ....


Edited :

I feel for you JimmyD.... Steve (I think it was) has lost some Silver Perch unexplainably when his temps got down below 5 degrees...

I think it would take a while for the fish to actually "starve".... but maybe the cold lowers their body temperature below a point where their internal organs don't function any more?

Or more probably they just acn't take up the DO from the water at those temps......

If you think about it - it's suggested that the humane way to kill a fish is to place it into a bucket of ice-slurry.....

I figure an ice-slurry would probably be about 5 degrees and definitely low or inaccessible DO which is what probably actually kills them more than the temperature?

.

Is the tank being heated at all, apart from the sun/ambient temp warming?
Silvers will tolerate temps down to 2o according to the DPI site http://www2.dpi.qld.gov.au/fishweb/2703.html but there may be other factors apart from them "freezing" to death