Backyard Aquaponics
A place to discuss aquaponics

First thing yellow perch (Perca flavescens) found in north america is different to english perch, redfin, eurasian perch (P. fluviatillis).

Second I thought FnF told me that he kept jades over winter without heating without any problems. Having said that he was offering a greenhouse heater for sale. Having said that just because he had one doesn't mean he was using it a he has/had lots of stuff he didn't use.

I understand what you are trying to do Jamie with the jades no/minimal growth over winter but fast growth over summer. Much better than no growth over winter with at best moderate growth over summer.

Coming from the other direction if you are going to spend energy why not spend it on cooling rather than heating and have trout all year round?

Ok so now all that's over......

Anyone still interested in group buy is quite welcome to join in.

There was a redfin thread on the forum a couple of years back......

Quite right. While they are not exactly the same, p. flavescens (the smaller of the two) is considered to be a sub-species of p. fluviatillis, but they are currently both being farmed in a similar manner. P.fluviatillis aquaculture pilots and small production systems are now established in a number of countries in Europe. There are some publications dedicated to the topic of redfin in aquaculture (i.e. Percatech project) if anyone is really keen. I was. I'm not now. The weaning methods are pretty much the same as with other fish though, with the twist of using lights at night in the US.

"In the USA, the habituation of yellow perch juveniles on artificial diets is directly
applied in some farms and results in rather good survival rates. When the fingerlings
reach approximately 17.0–20.0 mm TL, they are fed frequently throughout the day
with a commercial trout starter diet (mixed with krill). As they grow, the fish are then
fed with increasingly larger food sizes until they are harvested in the autumn. In
addition to feeding the fish on a daily basis, adding lights has proven to be effective
in getting this fish to feed on commercial diets. Yellow perch smaller than 50 mm (30-
45 days old) exhibit a strong photopositive behaviour, due to UV-sensitive cones in
their eyes. These UV-sensitive cones disappear when the fish attain about 50 mm TL.
Automatic feeders can be installed near the perimeter of the pond adjacent to the
submerged lights. At night, the lights concentrate large numbers of fish in the vicinity
of the feeders. The feeders then disperse food frequently throughout the night. This
modification increases the percentage of fish that initially accept the formulated food
and reduces total food use."

And in the Percatech project they started with mixing pellets with krill:
"Fish are placed directly in the tanks at 17°C at a density of 10 fish/L for weaning. They are weaned on a 700 mm to 1 mm cod diet (DanEx 1562). Weaning at the required density is important for reducing cannibalism and facilitating the transfer from natural to artificial diets. The fish wean quickly with most fish accepting the diet with 5 days."

From what I can establish however, p.whatevers are very slow to growout, and like tilapia, the females grow much faster. They are working on domesticating them, as well as establishing triploid varieties. Probably not too worthwhile to bother with in a RAS using locally available specimens it would seem, unless you had nothing more suitable or within the regulations to work with.

I don't believe however that there are any hatcheries raising yellow perch in Australia currently, and they too are not on the approved species for stocking list for Victoria (or other states I believe). And of course, translocation of live fish for stocking is not allowed either, unless purchased through a licenced hatchery. Deprived, yet again.

Maybe you should start your own thread and ramble on there. The above has nothing to do with this thread

That is exactly what we would be trying to do Stuart. So if anyone else is willing to give it go jump on board.

I hope I get an invite!!!!

matt

Yep its only the really hot days that trout can't handle the water temp...

I like the idea guys, I'll be following on with intrest

regards
Matt

Well, my Jade fingerling are currently Feeding lightly at 15c in the garage. I admit they feed much better at 19c and are ruthless at 22c but iv turned the heating off getting them prepared for the outdoors bout a week ago. if it was to dip down too much more i might put the heater back on.....

Just for those who are interested in my Setup, its 2 x 125L food grade storage tubs as Aquariums, they run chiftpist to a Solids Prefilter (Coco Scotch Pads in a some old steamer trays) that sits in a 200L barrel full of media, that go's to another 200L barrel as the sump. Iv also got 2 ABF's 1 in each FT with 25 Bio Balls in each and 50 bioballs floating round the sump.

I keep a 300w heater in the sump and run the system on a 15/30 timer. Everything has Lids to stop heat escaping free air. it sits at 20c with the heater on low.

I have not noticed it on my power bill. I feed very lightly twice daily. but the jades are growing like crazy

Weekly Maitence Concists of 25-50l water change, (use the excess on my dirt garden and fresh tank water in) and a clean of the scotch pads in the filter, yet again straight on the garden.

I had a lot of losses at the start of this system but its now stable as, not one death in months now, only growth!! Ph collapses and fish stress were the reasons for deaths.

Salt & shellgrit are handy

Ill Grab some photos when i clean up in there a bit... there is shit everywhere

do you have a post link to your jade system Jamey??

regards
matt

There was an old thread on the first setup i made, but it got fully re designed.

I will get some pics up soon

i'm thinking about getting one of my 200lt glass aquariums which is in the shed going again with a 300w heater on standby while we come into summer, controled by a temp control. Filtration is my biggest concern, but thanks for giving me a few ideas there Jamey.

Hey Bindy, my jades are in a 200L aquarium with a small canister filter, a 30L pressure filter and a small ABF. I reckon the filtration for the 22 jades is overkill but I had/made them so meh. Only got a 200W heater set on minimum and it keeps the tank at 18. I have a thread on it somewhere and will post some updates soon

Iv seen it in the "Flesh" its awesome much less agricultral than my setup

The ABF rolling the k-media is awesome