Backyard Aquaponics
A place to discuss aquaponics

Is that allowing for the fact that the fish keep growing? Like the difference between simple and compound interest?
Can you check your spreadsheet out using the trout we bought in May. They were around 50 grams then and now they are 360gms. I know that trout have a higher conversion rate.

Yep, it is compounded. At 2% feed and 60% conversion the 50 gram trout reach the 350 gram mark in about 160 days. I will email you the sheet.

Actually ... with most fish stock... the feed rate percentage is inversely related to size... although it is also dependant on water temperature...

Usually small fingerlings are feed multiple times per day... at a feed percentage of between 5%+ of body weight....

When near fully grown... the feed frequency may only be once per day... at a rate of 1-3% of body weight....

Here's an example Silver Perch Feed Strategy...

Thanks Rup, you can alter the feed rate and conversion % on the table I have made over time if you wish to look at a strategy such as that.

Thanks for the info Rupe.
Have received the shreadsheet thanks Mike, and altering the starting figures shows that if we started with fingerlings of around 50gms and fed them 3% they would be around 541gms after 160 days.
Does that sound right?
If so, that would be quite acceptable. Our temperatures can be quite high here in summer so this might be achievable.
Rupe said he would like to start with fingerlings of around 100mm. If they weighed 100gms, then according to the Burnsy chart those fish would be over a kilogram after 160 days at 3%. At 5% its an amazing 5.2Kg! That's at tropical conditions I guess.

Think you're a bit out in your starting guesstimation...

My 60-80mm Barra... average 6gm...

If you want to get really scientific... viewtopic.php?p=132722#p132722

Here's the Barramundi link... albeit PNG... http://www.publish.csiro.au/paper/MF9820663.htm

The person that lost the 14 barra fingerlings posted on this site about 2 weeks ago, problem with the fish from golden ponds is they are already pretty well stressed, most are white and all of them have the white stress stripes on there heads. They dont pack them in containers like hatcherys do, they simply put them into your supplied esky and you have to make sure there well aerated, the biggest problem is putting to many stressed fish in too small of a confines

A bit out! LOL.
So on Burnsy's formula a 6gm fish fed 5% for 160 days is going to get to around 300gms.
So does that seem right in your experience Rupe?

The woman at Golden Ponds made a point of saying that they won't be held responsible for any fish once they leave the premises. But it's a bit hard if they are starting out stressed isn't it?
How hard would it be to get an oxygen bottle and do the bagging oneself. I've seen them doing it in the shops. Is this an option?
Or maybe buy them interstate and get them shipped properly. LOL.

That's more like it...

Will a barra take 5% of it's body weight as feed every day? We were advised by Gav to be feeding trout at 1% so I would be surprised if a barra would take 5%, also does anyone know what the coversion rate of feed for barra is, the chart uses 50% but that may be to high (or low).

Fell for the same trap at the time Burnsy.... Gav was correct in his advice to feed 1%...

Because the trout aren't fingerlings... they're in fact "yearlings".... 2/3rds grown by the time we stock them...

And yep... with the right temp Barra will take 5% easily... I'm feeding 6 times a day with tank temp 26 degrees... probably close to 10%...

Barra will ALWAYS have the stripe no matter what, when you transport them. The slightest unknown shadow over their tank will cause them to get the stripe... And if you're willing to pay the extra I'm sure they will pack them as they do at other places, but no one wants to pay extra.

Good luck with getting interstate to ship to you, I sent a few emails of to a couple of them and they seem not interested for the quantitys we are after here in perth, yeh the ones at golden ponds are very stressed, Ive had mine for exactly a week now and quite a few still are fairly white, plus the cold temps here in WA havent helped out latley.

Make sure you have plenty of airation and try not to cramp too many into the one container