Backyard Aquaponics
A place to discuss aquaponics

KP, I measured nose to tip of tail.

+1 for nose to tip of tail being the normal way to measure all fish

Yep, I vote for laying it down and measuring from tip to tip...

Sampled a couple today...

200mm - 138gms
250mm - 243gms

Couple more...

200mm / 130gm
220mm / 160gm

Another couple..

225mm / 160gm
235mm / 175gm

Had a perch for tea tonight. 460mm 1.5kg. Looks like its too big to put on the graph. Actually found it to be a bit chewy and like trout I feel that the smaller sizes seem to be the best eating.

First glance I thought it was a Golden... but definitely a Silver by shape...

Take it from the colour it's been dam raised Troutman???

Yeah Rup raised in the ponds and spent the last few weeks in the tank.

How old would it be Troutman ... 2 years... or more?

Probably double that Rup, we dont get the long growing season down here that you get in NSW.

Hi everyone,

I just found this thread in a search because it could be usefull for what I'm dreaming of attempting. It seems to have lost some momentum though. Is the topic being covered somewhere else?

If this information can be gathered for all the AP species (barra and trout mostly) I can make some educated guesses about how big my nursery system might need to be.

My idea is to make a small system, hopefully mobile so I can move it into the sun or shade, that I can control the temperature in to get a jump on the next seasons stock. My theory is that system of X size can carry a fish load based on their final growout weight, but if the 'final growout' weight is measured at, say two months, what fraction of that 'X size' can my nursery be?

Dex.

Species differ slightly in oxygen demand, especially fast growing species such as Barra & Trout... and by the sheer nature of their accelerated growth rates are fed more often, and larger amounts... which in turn has an oxygen overhead... and filtration requirement...

In general, the same safe, recommended minimum filtration ratios, water turnover, and stocking densities....apply regardless of size of fish... at least when designing your system...

Yes, when small fingerlings, you can stock more... and/or with less than optimal filtration ratios... assuming you will remove fish or add more filtration when you approach the limits...

But that involves a degree of knowledge and understanding in order to know when your approaching the limits... and the time availble to manage it all...

Of course the fatl mistake, that is often made... is to double your stocking density, while halving your filtration capacity...

If in doubt.... size your "mini" system to the same suggested densities and ratios suggested...

Does anyone have a safe way to measure the weight of live fish on a regular basis, or are all these records of losses? If you do measure a selection of your stock, how do you take a representative sample?
Sorry. That's more a total fish load question than contributing to the thread.

The "weight vs length" graph is a combination of fish lost... and fish harvested... or fish sampled...

The easiest way to measure your Silvers... is drain down your tank, add clove oil.... measure about 5-10 fish... average....

Refill tank to revive from the clove oil...

If you're doing this... then you might as well weigh the sampled fish as well... which will allow you to determine the bio-mass in the tank... and appropriate feed rate...