mixing it up

Worms

Hi all,

I thought it would be handy to know what people's experiences on polycultures have been..i.e. what grow together and what don't. Even same species of different ages. I have the oppotunity to purchase silvers, sleepy cod, cat fish, goldens and murry cod and would love to chuck them all in the same tank......but is this a good idea.

also, are fresh water mussels a handy additive along with afew glass shrimp.

always learning,

worms

janethesselberth

I had larger goldfish mixed with tilapia fingerlings. They did just fine.

I just put tilapia fingerlings in with near-eating sized tilapia. No signs of violence, but I do worry that the fingerlings get crowded out at mealtime. Time will tell.

cubonic

I have marron and goldfish (mainly comets) in a pond system and both survive and breed.

The goldfish school has a couple of koi in it (about 15-20 cm).

There is plant cover for the goldfish breading and good overhang cover for the marron.

These ponds are stocked at reasonably low densities (<1kg of fish and crustaceans per 1000L.) Thus at low densities marron, goldfish and koi can all go together. I suspect the koi do not bread because they are either too small or are of the same sex.

I have also had bream in the pond with goldfish. The bream slowly over 4 months or so disappeared. Food availability, cold and low salinity for the bream were probably more a factor than the goldfish.

Typically this system is left to fend for itself. Until recently I have not been adding feed or growing food plants in 400L gravel filter for the continuous flow artificial stream that connects them. Thus the inhabitants had every incentive to eat each other. (There is significant detritus falling and blowing in to the pond from surrounding vegetation.)

The pond system is over 5000L.

RupertofOZ

Welcome to the forum Cubonic...... how about starting a thread of your own in the members section and including a few photos.

I'd be interested in any info you have on breeding marrons.

cubonic

I did not have to do anything special to get the marron to breed. The only thing that is a little unusual is that they bred in autumn or winter. The books on yabby breeding suggest they breed in spring once the water temperature increases. They may be doing that this year as I have seen them together more but last year it must have been later as I re-lined the ponds late last spring before the marron went in.

I had trouble with the gravel filter for a while and took it out of circulation for a while so the turbidity would have been higher than usual which may have helped the young survive once released.

This year I will put any females I see with young in a separate system about the time of release to see I can increase the survival rate of the young. It looks like only one in ten survived to be 5cm or so long. When they have young they are really hard to find and good at hiding so I may not have any luck finding them. In fact it is very hard to get a count of how many there are as only a few are out foraging at any one time.

twintragics

your glass shrimp will last 5minutes. Murray cod will eat everything in the tank, even each other. Sleepys really need the heat dialled up, (like 26C plus.)

Silvers and cats will be fine together, goldens can be hard to get on artificial feed. If you are getting goldens from aussiefish, they will already be on pellet food tho. Don't know anything about mussels.

aeldric

Provide lots of hiding places. I put the follwing together:
5 large silver perch
5 Tandanus (cat fish)
5 yabbies
5 freshwater mussels

A lot of literature suggests that the tandanus should be OK with silvers, because the tandanus ae bottom-feeders and silvers ae not. The mussels and the yabbies were always going to be a risk, but I tried it.

The silvers took bites out of the mussels every time they tried to come out of their shell. The mussels died.

Then the silvers ate the yabbies as they moulted.

Then the silvers went after the smallest of the tandanus.

After 6 months I was down to 5 silvers and 2 tandanus

A few months later the silvers got the last 2 tandanus.

I think the problem was the size difference. The silvers are plate-size, while the tandanus were fingerlings

steve

at leat the dead went to a useful place (fish weight

)

Don the fish feeder · **Joined:** Oct 7th, '07, 21:11 **Posts:** 372 **Gender:**

SIlvers are nasty fish, even bass aren't safe with them. Barcoo grunters usually last ok with them in my aquarium experience.

steve

Quote:

SIlvers are nasty fish, even bass aren't safe with them

U serious?

i've found them to be quite chilled out

EllKayBee

Quote:

even bass aren't safe with them

I didn't know that, thanks...my goldfish population has also decreased to zero since mixing them with SP.

King Erik the 14th

I put some info on another page recently:
http://www.backyardaquaponics.com/forum ... php?t=2215

Quote:

I had a brief chat to a guy (Neil) who trained as a vet and went on to specialise in fish and fish diseases. He recently wrote a PHD on a barramundi parisite which he discovered. He's got alot of experience with commercial aquaculture and is currently working in buisiness to to establish a commercial aquaponic farm north of Adelaide. When I told him about my system and the 3 different fish species I had together, he went onto warn me about the perils of keeping more than one species in the same system. I explained that I was planning to have a winter crop (trout) and a summer crop (silver perch or catfish). The concern is not that they are in the tank together but rather that they share the same biofilter. He described that in a river you have many different species together, but at extreemly low stocking densities and water is constantly being replaced. Things work differently in a reticulating system with a high stocking density. Different fish species have different gut flora, and these are going to be in relatively high concentrations in a reticulating system. But while one species will cope with its own particular gut flora, a different species wont and could die or at the very least wont flourish. He attributes this as the main reason why some aquaculture ventures have failed.

I know that there are plenty of us here that keep more than one species together, Neil suggests that you might want to reconsider this. He says you might get away with it at low densities, but at high stocking you'll probably run into trouble. On a positive note he said that your growth rates and fish production/harvest will be greater if you keep just one species for the whole year, compared with two different species as I had planned (a winter fish and a summer fish).

I didn't get any technical data or references but I'll ask next time I see him. I have invited Neil to come to an SA AP meet but am waiting for his reply. Something to think about + discuss, and i could perhaps forward any questions to him. Has anyone else got any info about this?

I still havent got any evidence/research/papers to back it up though.

Worms

geez, didn't realise this thread was still going, thanks for the info.

tt, figured that with the glass shrimp but thought they could be a good live food source if easily bred.

didn't realise the mussels were at risk from the silver though, i'll fish them out and put them with the yabbies.

One thing i have discovered is small silvers with large ones seem to be ok.

got a 4ft aquarium from work (the tip) with a light and stand. set it up today today to better observe the combination and interactions with each species ive got....or thats what i told the boss anyhow.

Don the fish feeder · **Joined:** Oct 7th, '07, 21:11 **Posts:** 372 **Gender:**

Ya I have kept a lot of native and aquarium fish together. silver perch can outkill most things around their size.
They more thin the herd than just wipe out tanks tho.
Keep them well fed and they aint so bad.
but ya in aquariums nasty fish

Don the fish feeder · **Joined:** Oct 7th, '07, 21:11 **Posts:** 372 **Gender:**

Just add that when you have fighter fish, you often keep them sepperate to other fish. When you mix with community fish (tetra, guppy,goldfish) they often pick up diseases they have never encountered (no resistance to) before.
A lot can be said about quarantine for new additions and cutting live fish/shrimp out of the diet.
Anyway a perch is like a little bullshark.... opportunist forager.

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mixing it up

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A place to discuss aquaponics