Backyard Aquaponics
A place to discuss aquaponics

How cold is too cold for Silver Perch?

This webpage says SP will tolerate temperatures down to 2 deg C.

How cold have you had your SP? I know Mr 10,000-posts had his SP at 7 deg C before they died (but perhaps not due to temperature-related issues?).

My SP are only small - will they tolerate the same cold temperatures as "adult" SP?

think they may have been the jades.......... i think i've had the silvers down a bit lower, but cant remember.............

All the literature that I have read, says not to constantly run below 5 deg c, which should not be a major problem in most areas of Oz.

Bigger fish will handle to cold better too.

Hi Steve,



No need to worry about AP-memory-loss while this forum is around:

See your previous post on this topic.

From Natfish notes....

Silver Perch is a temperate, warm-water species that can tolerate water temperatures of 2º to 32ºC. Optimum water temperatures for growth are between 17º and 26ºC and growth is negligible below 12°C.

Never mind the SP's ,, I think I would die at 2C.

SP's as per NSW Primary Industries ,, survive 2-38C , optimal 23-28 C.

Sounds surprisingly similiar to me ,, perhaps I was an SP in a former life:)

Sorry Rupert ,, we posted at same time.

Hi Outbackozzie,



Where "constantly" is measured in ... hours? days? weeks?



I'm not sure about that. (Hence why I created this topic to find out about APers actual experiences.)

Currently my mean maximum water temperature is ~15 deg C.

Currently, Sydney is experiencing mean minimum temperatures of ~13 deg C & mean maximum of ~22 deg C. In mid-winter we can expect a mean minimum of ~7 deg C & a mean maximum of ~17 deg C.

It seems reasonable that my mean maximum water temp will fall to at least 9 deg C.

The above does not account for the minimum mean temperature (caused by daily water temperature variation, coldest in the early morning) or what happens during prolonged bad weather. ie. a cold snap.



I'm trying to fatten them up, but they're growing so slowly. I think my fishies must be sneaking off to participate in "The Biggest Loser" when I'm not watching.

ROFLMAO

Scott - I dare say like a lot of fish SP can tolerate a day dip in temp below 2-5 deg c (unlikely) (when did you last have two days in a row below 5 deg c?) During the colder weather I just reduce the night time pumping, and increase the day time pumping.

In Sydney ..... how far west are you? Temperature here ,, near Cronulla is 18 C ,, ground temp around 20C.

Check my thread on Temp and DO levels ,, been copping a bit of flack but think I'm on the right track.
Sydney now in a stabilised tank would be good for those WA trout , not so good for SP and what I want to grow being Jade Perch , hence my playing with various heating ideas.

Hi Chappo,

I live in Westleigh, close to Hornsby.



I think you are the geographically closest APer to me. For some reason there seems to be very few APers in the largest city in Australia.



Ah, I assumed (incorrectly) from the topic name that you were asking about what happens to DO levels as temperature varies.



I've spent quite a bit of time thinking about how to keep my fishies warm.

The leaching of chemicals (at warm temperatures) from poly tubing is a PITA. Otherwise, a passive solar heating system would be quite straightforward & economical (IMO).

i stand reminded

yeh, trick is to reduce pumping. the GB's is where all the heat is lost. use an airstone and cut pumping between say 8pm and 8am

scottie ,, yep looks like it just us in the "big smoke"..... Hornsby ,, a fair bit further from the oceans steady temp , explains the different temps.

Steve ,, could also have standard garvel bio filter in same warm insulation as fish tank , don't want those nasty nitrites building up . Bacteria happy at warmer temps also.

Did a quick search on off-peak elec prices ,, can get 15 % lower than what I'm paying now ,, so previously quote heating prices ( other thread) just dropped, 15%.
Cheap as chips ,, and at the same rates I pay now ,, greener people can get "green power".

Steve, I have a small air pump with airstone running 24 x7 in my 1000L IBC. Could I stop pumping altogether during this period? Will this affect the bacteria? I currently pump 30 mins on (takes 20 mins to fill) , 1hr off to a single bath tub grow bed wiwth 15 silvers (small 6 -15cm).

thanks

Stopping the pumping would not affect the bacteria. Make sure you set the beds up so that they drain when the pumping stops. They will of course stay moist through the night. Your issue will be making sure there is still adequate biofiltration. An enclosed biofilter - preferably out of the weather, that runs in conjunction with your beds and stays on at night during winter is the go.

I need to do some experiments to see how big a biofilter is needed to keep things sweet through the night, varying with different final feeding times. The theory is that if the fish are fed a few hours before the beds go off for the night - hopefully much of the poo from that feed - or forced out from the previous feed is in the beds and therefore ammonia creation during the night is reduced??? I have no idea though about the digestive cycle of fish (how quick is it???), but of course fish release ammonia through respiration regardless of the feeding and digestion cycles - hence the importance of biofiltration 24/7.

I figure the only way to get the answers I need will be to have a late night and do hourly water tests till the early hours - with beds off - to see what sort of levels happen during the night. I have a small biofilter (20 litres of hydroton) that runs on top of my tank in the shed at all times, but highly doubt this will keep things in check through the night for my 100 barra.