Backyard Aquaponics
A place to discuss aquaponics

Currently I've got a tank full of jade and silver perch. The silvers are fighting a lot and often inflict puncture marks and small wounds on each other. I've tried culling the dominant ones, but other fish just take their places and start behaving aggressively.

So I found a supplier of sub-adult Murray cod and was thinking of switching.

Any Murray cod enthusiasts out there that could tell me how they perform in a tank?

Cheers.

They eat each other unless you can grade them into separate tanks according to size. I started with 150 Murray Cod 12 months ago, and reckon there are only about 40 in there now. However, this does lead to a faster increase in the average size as the small ones vanish!

They do tend to eat each other, I have 5 left from 50.
Next time I'll keep them in a smaller mesh basket inside my fish tank to keep them more densely populated. I hear that is 1 way to stop them from eating each other.

I'm interested in your Murray Cod supplier......?

I bought mine from Narrabri Fish Farm

How many fish do you have? Generally Silvers aren't an aggressive fish if you have a few in there. We found in the past that if one or two fish seemed to be getting aggressive it's because the numbers were getting low, pop in some more silvers aggressiveness goes away.

I've heard they're very cannibalistic as they begin to mature from the fingerling stage, but the fish I'm looking at are all close to a kilo and a uniform size, so I don't think cannibalism will be an issue. I was more interested in how the more mature fish would co-habitate together as a group.

Lyndon364, the fish are in tanks at a fishmongers near me. I'd love to know who their supplier is because they always have an excellent supply of big live fish. So far I haven't been able to find anyone in Melbourne that sells live fish of this size. They sell live bream, barras, cod and perch for around 22 bucks a kilo. I reckon it's pretty good value if you want to skip the fingerling stage and just have a few large fish in the tank. Currently I've got ten adult silver perch, three younger jades, a pretty large barrumundi and a gibbyceps catfish all living fairly harmoniously. The only problem is that the silvers are aggressive towards one another, but they hardly ever harass the other species.

Earthbound, yeah I was thinking about that, crowding them a bit more. There's ten silvers in a 1000 litre tank, so plenty of room in there.