Backyard Aquaponics
A place to discuss aquaponics

Not sure about the beef- they wouldn't eat anything else, other than Blood Worms, and they are far too expensive for long term feeding, but ok for small fingerlings. I've tried 5mm pellets the past couple of days, but still no interest in them.
Murray Cod, being freshwater fish, wouldn't be eating any seafood such as found in commercial fish pellets, in the wild. I think it would be mainly smaller fish, bits of various dead or alive animals and birds and bugs.

I'm not a fan of Teflon Colum, I've had too many frypans that gradually become worse and worse, no matter how well I look after them, and I'm pretty sure it gradually releases bad stuff (technical term) over time in the inevitable times it gets too hot. Cast Iron is tops.

Another 2 dead ones at 8pm, well one was still just alive when I pulled it out, but is no more. I think I might do a bit of harvesting tomorrow- anything that I can't catch is probably ok.

I agree with you on the cast iron, great for red meats and chicken, but you can't beat teflon for crispy skin fish. Plus with those mats, if it gets bad, just take it off and replace.

You could feed some feeder fish the pellets, and drop them in there, so they are getting the pellets in a way?

Now up to 16 deaths, although I did have to whack a few on the head as they were still just alive.
Probably not related to the deaths, but this one had some non-pigmented patches, perhaps old injuries? on it.



I gave one ~150g tiddler to the chooks, as it had a bit of brownish liquid coming from its bum. The chooks weren't sure what to make of it- a few pecked, but most stood well back watching it intensely.

I've handled a couple more as in the latest video, and they seemed quite active and took off fast, so at least a few of them are not too close to dying yet.

3 eaten, and we are all still alive
1 to the chooks, 2 in the fridge, and 10 in the freezer- I reckon I'm half way or more through them now.

The new trout smashed 40g of pellets this morning, even though the water only cooled to 20C overnight, so they seem unaffected by whatever is killing the Cod.

Current theories are: too much ox-heart over a few months and they are all having heart attacks- some of them have quite a lot of fat deposits in the cavity. I'll get a pic of the next one, but not all had that.

Or a feed of ox heart a week or 2 ago was a bit off, - it was changing colour, but wasnt yet "off" although I
wouldn't have eaten it (even if I was inclined to eat such things ). The chooks ate the most discoloured stuff and they are fine.

Or water added, of which some had been stored in a galvanised tank, a few hundred litres in ~7000l total, so I think it is unlikely to be the problem, and the trout in the same water are fine.

Or something introduced with the trout, but I see no obvious signs of any disease

Basically, I have no idea what the problem is!

What about trying to give them actual fish pieces?

Get a cheap hake fillet or something, chop it up and drop it in? See if they go for it?

How many are left?

Not sure of exact numbers left, but last time I tried to count I didn't make it to 30, so I'm sure less than half are left.

I might just drop in a bit of one of the tiddlers and see if they go for that, as I know they eat Murray Cod! Special trip into town and back = 70km, hake becomes not so cheap!

They didn't go for any fish pieces, and the last death was on 21/4, leaving one Murray Cod remaining in the tank, which seems to be behaving normally. I'm suspecting the ox heart food as the problem, as the ~215 Rainbow Trout are still fine, and they are in the same water. It certainly was not due to lack of Oxygen- ~30 cod in 4000l of water with a bit more aeration than 215 trout in 1000l of water, and no problems with them.

I previously thought I might get M Cod again, but looking at how much I spent on food and how small most of them were when they died or I whacked them on the head, I don't think I'll bother trying them again.

That must be one happy Cod in the 4000L tank my himself.

I hear they'll grow quite big when alone and happy.

Perhaps, but its a bit of a waste having all that space for one fish, which certainly wont support the 9GBs! It doesn't seem to be eating anything much ATM, and probbaly wont until later in the year when the water warms up, so its days may be numbered. I might have to see if I can locate another 100 trout fingerlings soon.

Wow Gordon, I can't imagine 215 trout in 1000L, there must be more fish than water! It just shows what you can do when you know what you are doing . I stress enough about my 25 which are all over 25cm now except for the 2 runts that barely make 20cm.

Plenty of aeration is the key! The shoal is gradually expanding, getting up to about half way around the tank (but not full depth), so I will have to move them soon, before they really do run out of space. There isn't a fast enough water flow to clean all the poo out via the SLO, so I have a bit of a water vacuuming session every now and then, before too much accumulates. I would like to increase it, and use a larger SLO, but a certain starry tracking company appears to have lost all my poly fittings, so things have been delayed.
The largest of them is getting close to 20cm, and smallest ones are ~10cm.

Autumn is coming! There have been a few cold days which have dropped the water temperature quite a bit, and about 3 times the average rain for April.
All the 215 new trout are still in the 1000l tank in this system, while I wait, and wait some more, for my poly fittings to arrive. I know I need to get them out of there ASAP, as quite a few seem to be about 20cm long now. They weren't interested in eating this morning, perhaps due to the falling pressure over the past few days.

The lone Murray Cod is still in the main FT, but hasn't been eating, other than perhaps a bit of biofilm.

Gordon, I'm so sorry I only just caught up with your post. That's why you have 4000L free? I thought you had extended. I know yr always doing something.

Haven't read the full thing but did you salt when you added the trout? Seems very coincidental that you're having these probs immediately after adding the trout. Remember when I lost all my SP? Same thing (although there was debate about the type of salt I used and the temperature of the water).

I guess that's one prob with having dual systems, too many variables.

Glad you at least got to enjoy your cod but looking forward to hearing how your trout go.

It's still a bit of a mystery as to why they died, and the one left seems healthy enough. No sign of Ich with the new trout, who did have some salt to start with, nor the M Cod. The trout are still all alive and very hungry most days, and I really do need to get them into their new FT soon, it's getting crowded!

A visit by Steve (Rendang) today saw my lone Murray Cod gain 120 new friends, in the form of Rainbow Trout.
Thanks Steve and Ben! 121 fish now in the ~4000 litres of water in my first system. Water was 1C cooler in my tank and pH 0.2 lower, so we tipped them straight in.

After we tipped in the first drum of fish, one appeared to be stationary on the bottom, but suddenly came to its senses and started swimming around like the rest, which include a few deformed ones, so I'll keep an eye on how they go.

So now I have 335 trout, 10 Atlantic Salmon and 1 Murray Cod between my 2 systems.

Great news, big drive for Rendang. What on earth are you going to do with all those fish? Got any recipes for cherried trout or trouted cherry?