Backyard Aquaponics
A place to discuss aquaponics

Just had a look back... and I think the ones above went in maybe mid May??... might have been end of May...

So around 4 1/2 months to roughly 500gms...

Pulled a couple of fish out again this arvo to cap off a great long weekend. One was a monster that jumped out of the net as I was transferring to the bucket, so he lives to eat another day!
One that stayed caught was just over 1kg and 38cm and the other just under 900gms. Not bad for 5.5 months (went in just after Easter).
A lot less fat in them this time since they have been on a diet - only 500gms of food a week for the last month or so.

Excuse the blood in the photos.



Noticed one of the fish had only rudimentary anal fins. I'm sure if he had had them he would have cracked the kg


On the larger of the 2 fish i noticed white marbling through the flesh after they were cooked, any idea what it might be?

Fat....

What was the clean weight (gutted and gilled)?

Marc:

Those are huge man. No wonder you nitrates are sky high, you must have been throwing food in by the bucket full

Interestingly a few of my larger trout had a bit of fat around their stomachs too. Not as much as yours though. My smaller ones had a lot less to none. Shows how important sizing your fish is if you were running a commercial system!

Here is the last of mine. Largest was 500g gutted and gilled and measured 330mm long.

873gms gilled and gutted.
they may look heavy in the body but there is a lot of meat and they are much thicker than the others.

I have "normal" looking trout in the tank as well and they are around the 650-750gm whole. Perhaps they are the ones that dont get as much food; who knows.

My "mutant" trout and the jumper were almost cylindrical in shape and very heavy for size with very thick and dense flesh, however, the one I ate ended up losing over 25% of its mass in guts and gills, although there wasn't excessive amounts of fat. Smaller fish from my system have much more "normal" shape and only give up about 10-15% of their mass when cleaned; much better bang-for-buck.


How many fish in your system to be eating 500g of feed per week, approx 70g per day?

At the moment my 11 remaining trout (guestimated average 700g ea, so similar to yours) are only taking 20-30g per day (about 200g per week) which is only about 0.4% by weight and have been doing so for a few weeks now; when allegedly they should be taking about 1% by weight, or more than 2.5 times as much feed as they are currently taking. It makes me wonder about the feeding schedules provided by the feed manufacturers and the research on which the figures are based. Does anyone actually follow the feeding schedules? If they do, how much waste (uneaten food) do they end up with?

Not that I'm concerned with small amount of feed mine are taking, but I still have some feed leftover and if the renovations had gone according to our original schedule I would have had a lot more wasted feed as we would have pulled all the fish out by now, but (un)fortunately (depending on your perspective) the renovations are somewhat delayed. Cooler weather for the remainder of the week and the delays in getting the tradies on site means the fish live another week or so to eat the last of the feed, then it's time for final harvest and fishless AP for a while until the backyard work is complete.

When I was feeding that amount I had 25 fish in the system. If I followed the "Rule" of as much as they will eat in 5 mins, 2 or 3 times per day they would eat substantially more than that, easily well over a kilogram per week.

I don't know why mine are pigs but they easily will eat more than the recommended amount. What is interesting is that the pH was about 5.5 (I was caught by surprise as I have a lot of shells and about 250gms of ground limestone in the system) and the nitrates were high (800ppm) so not the best for the fish yet that did not put them off their food. Once I brought the pH back up and the nitrates down to 200ppm the silvers started smashing the food when before they were not interested (at a similar temperature). The trout stayed the same.
The water from the trout tank goes into the silver's tank and has a net to catch any food that may be uneaten. Very little food was caught by the net and none was left in the tank. The water is very clear and I can see the bottom, making checking fior uneaten food easy but does take time (that's why the net is useful)


There does appear to be two distinct types, mine like yours have a very think and dense flesh, although the guts and gills weren’t near the 25% mark in the last couple of fish. This could be because they are the pigs and get the bulk of the food or perhaps they are a slightly different form. When I was feeding as much as they would eat, all the fish should have got what they wanted, so I got no idea.

Awesome harvest Ryan, you have got to be happy with that.

You prompted me to do a water test (hadn't done one for a while). My pH was 5.3! My shell grit must have finished dissolving a few weeks ago as the last water test on 28 August showed a "stable" pH at 6.2-6.5; proving the role of the buffer material. This might also explain the recently wilted silverbeet and lack-lustre kale (which have been replaced with summer crops anyway). Ammonia was up a little from normal, but they were fed just a few hours before; nitrites are still zero as they have been for ages; nitrates are around 80 which is slightly raised for my system but easily explained by the fact that we ripped out the winter crop last week and weekend and have only just added the summer plantings.

In any case, my fish have always been small feeders, regardless of the history of system pH, yet I still get very good growth rate (IMHO) for the meagre rations I feed them! I think my final FCR will still be as out-of-whack as the interim value I have now with the fish just about adding more weight than they're provided in food, instead of the published value for rainbow trout in the order of 1.2


Did you get your fish from Gavin? Maybe he's got a mutated/mutating gene in his fish, or is it present in all fish? I guess I will find out when it comes time for the final harvest. All-in-all, they're still good fish... if only I could smoke them properly now

Was going to pull two trout for the missus and I for dinner but this one will do the both of us. 717g and 600g gilled and gutted.



Getting ready for the barby

First cull!!

Knife is 35cm long


here is the biggest!!


And the smallest, a good looking buck, was just starting to develop his hook jaw.

IceMan, your smallest weighs more than my largest so far: you are a braggart, plain and simple!
They are indeed six beautiful fish, apart from the munted tails, that is.

cheers mate... i was shocked to how big they grew to.

as for the tails that would be due to the nitrite issues i experienced early on in the piece.

The one that is second from the right weighed in at 468grams today and only 204 back on the 2nd of last month... that growth is scary!!

awesome harvest iceman.
any more left?
what is the greeny fish on the far left? i have one like that as well. i keep putting him back 'cos he is different!