Murray cod
- Thread starter ashdavid
- Start date
Hi guys, great site, great thread.
As somone who takes the biology and the conservation of the Australian cod species seriously, it's nice to see such interest in them. Thought I could assist with some of the things people were wondering about.
Actually Murray cod can grow very quickly in seasonally warm water temperatures to about the 50-60 cm mark. Most Murray cod can hit 60 - 65 cm in 5 years in seasonally warm water temperatures and food rich conditions. In one newly flooded warm impoundment a 4 year old fish weighing 12 kilos was recorded, though this water an extreme growth rate.
They are live food specialists in the wild, taking other fish, crayfish and other living creatures opportunistically. Yep, in tanks they can become fussy and spoilt and quickly get to the point where they refuse to take anything but live food. Some owners don't mind this ;-) The only way to avoid this is to feed them lots of dead foods and keep live foods an occasional "treat".
All cod species are big, slow growing, long-lived, territorial, aggressive species with a relatively low fecundity. They are incredibly vulnerable to overfishing and habitat degradation. As indicated above, all the other cod species and sub-species are in BIG trouble. There's a lot of concern now over the future of wild Murray cod stocks too.
Cod have wide temperature tolerances, from roughly 4 degrees through to the low 30s Celcius, so they certainly don't need heated tanks.
However, Optimum temperatures for growth and comfort of fish is much more restricted. Cod don't do much growing below 20 degrees, almost none below 18 degrees. They do most of their growing in the warmer half of the year - late spring, summer, and early autumn. An excellent all-round temperature for them in a tank would be around 24 degrees.
I have grown my Murray cod to almost 30 centimetres in less than 12 months. Even though Murray cod don't need tank heaters - and I don't use a heater now - to get my Murray cod from the tiny stage to the start where he could start eating feeders, I kept the tank at 24 degrees for the first few months, and fed him tons of whitebait, prawn pieces and small live shrimp. Once he was big enough to take feeders I gradually turned the heater down and then removed it. Now he lives in an unheated tank and is fine. As mentioned above, they live in the temperate parts of Australia and cop cold temperatures in the wild, so they can handle them.
I suppose in finishing I would say that Murray cod are indeed a great fish and a unique Australian animal. They are certainly worth keeping. They are very beautiful in their colouration and markings, and have a lot of personality and character for a fish. They are aggressive and territorial and they DO have big mouths. It is usual for all tanks companions to be either beaten to death or eaten. But a single cod in a large tank is more than enough entertainment, especially with live feeders.
Murray cod certainly should be of interest to people keeping BIG fish in aquariums. Most Murray cod will reach 15- 20 kilos if fishing pressure and food resources allow, and some will reach sizes of 40 - 50 kilos. They have been aged to 49 years old and definitely reach ages in excess of 70 years. A great fish indeed.
cheers
Simon
As somone who takes the biology and the conservation of the Australian cod species seriously, it's nice to see such interest in them. Thought I could assist with some of the things people were wondering about.
Actually Murray cod can grow very quickly in seasonally warm water temperatures to about the 50-60 cm mark. Most Murray cod can hit 60 - 65 cm in 5 years in seasonally warm water temperatures and food rich conditions. In one newly flooded warm impoundment a 4 year old fish weighing 12 kilos was recorded, though this water an extreme growth rate.
They are live food specialists in the wild, taking other fish, crayfish and other living creatures opportunistically. Yep, in tanks they can become fussy and spoilt and quickly get to the point where they refuse to take anything but live food. Some owners don't mind this ;-) The only way to avoid this is to feed them lots of dead foods and keep live foods an occasional "treat".
Murray cod have fared better than the other cod species and sub-species. While all of the other cod species and sub-species are endangered or critically endangered, Murray cod are listed as "Vulnerable" under most state legislation and under Commonwealth (national) legislation.
All cod species are big, slow growing, long-lived, territorial, aggressive species with a relatively low fecundity. They are incredibly vulnerable to overfishing and habitat degradation. As indicated above, all the other cod species and sub-species are in BIG trouble. There's a lot of concern now over the future of wild Murray cod stocks too.
Supposed to be good, but then Golden perch (another native) are supposed to be good too, and they're very ordinary. Haven't tried to eat Cod, don't intend to. Could never kill one.
Migration in cod species is not fully understood yet. Most are showing that they can be quite migratory at times. With Murray cod, larvae deliberately drift downstream at night for 4-7 days after leaving the hatching site, and adult (radio-tagged) Murray cod have been recorded migrating up to 120 kilometres upstream (during floods and freshes in late winter and early spring) for spawning. What is remarkable is they then head back downstream and return to the EXACT SAME SNAG (sunken tree) they left from.
Even though they get close to sub-tropical latitudes in their natural distribution, the cod species are basically temperate fish species.
Cod have wide temperature tolerances, from roughly 4 degrees through to the low 30s Celcius, so they certainly don't need heated tanks.
However, Optimum temperatures for growth and comfort of fish is much more restricted. Cod don't do much growing below 20 degrees, almost none below 18 degrees. They do most of their growing in the warmer half of the year - late spring, summer, and early autumn. An excellent all-round temperature for them in a tank would be around 24 degrees.
I have grown my Murray cod to almost 30 centimetres in less than 12 months. Even though Murray cod don't need tank heaters - and I don't use a heater now - to get my Murray cod from the tiny stage to the start where he could start eating feeders, I kept the tank at 24 degrees for the first few months, and fed him tons of whitebait, prawn pieces and small live shrimp. Once he was big enough to take feeders I gradually turned the heater down and then removed it. Now he lives in an unheated tank and is fine. As mentioned above, they live in the temperate parts of Australia and cop cold temperatures in the wild, so they can handle them.
I suppose in finishing I would say that Murray cod are indeed a great fish and a unique Australian animal. They are certainly worth keeping. They are very beautiful in their colouration and markings, and have a lot of personality and character for a fish. They are aggressive and territorial and they DO have big mouths. It is usual for all tanks companions to be either beaten to death or eaten. But a single cod in a large tank is more than enough entertainment, especially with live feeders.
Murray cod certainly should be of interest to people keeping BIG fish in aquariums. Most Murray cod will reach 15- 20 kilos if fishing pressure and food resources allow, and some will reach sizes of 40 - 50 kilos. They have been aged to 49 years old and definitely reach ages in excess of 70 years. A great fish indeed.
cheers
Simon
Just realised that my post sounds a bit contradictory in that I said Murray cod can grow quite fast, but described the cod species as a whole as slow growing.
Just to clarify, cod species can grow quickly in food rich conditions, but in most habitats in the wild grow more slowly. Also cod species grow very quickly to the size of first sexual maturity (50-65 cm) and then slow down quite a bit. The rub is that is fish well into this slower growing stage that are the best and most fecund breeders.
cheers
Simon
Just to clarify, cod species can grow quickly in food rich conditions, but in most habitats in the wild grow more slowly. Also cod species grow very quickly to the size of first sexual maturity (50-65 cm) and then slow down quite a bit. The rub is that is fish well into this slower growing stage that are the best and most fecund breeders.
cheers
Simon
I just found this forum today, and GooDoo, you beat me to it.
I have kept Murray Cod in the past, and curretnly have 1.
The last 2 that I had I had to sell due to them outgrowing their tank.
I had them for just over 12 months. Originally purchased at 3 Cms, they grew to 30 Cms before I sold them.
They are now happily living in their own tanks.
I do not have any type of heating in my native tank. The temp does change, and quite dramatically during the year as well. From as low as 14 degrees in winter right up to around 35 degrees in summer.
They are a slow growing fish in the colder months, however they do gow quite quickly in the right enviroment.
As for importing, I don't know if this is available.
If it is, I would suggest to those who are thinking about getting one out of Australia to buy a huge tank, as releasing them into the wild over there is not a good thing. (this is how carp got into our waterways.)
Carp is one of australia's biggest vermin. It is illigal to relase them back into the water, even when dead as their eggs have a huge survival rate even if the carp is dead. I usually just leave them on the bank after cutting their throat. Or use them for bait for other types of fishing.
Cod, in my opinion would have to be one of the best tasting australian native fish, however due to increasing numbers, I only get to 1 a year.
As some-one else has suggested, golden perch is another great tasting australian native, some say that the goldens are almost as good cod, I doubt that.
Hope some of this info helps.
GooDoo knows a lot about australian natives, so I woudl take notice when he has something to say about them. I have learnt lots from him on other forums.
I have kept Murray Cod in the past, and curretnly have 1.
The last 2 that I had I had to sell due to them outgrowing their tank.
I had them for just over 12 months. Originally purchased at 3 Cms, they grew to 30 Cms before I sold them.
They are now happily living in their own tanks.
I do not have any type of heating in my native tank. The temp does change, and quite dramatically during the year as well. From as low as 14 degrees in winter right up to around 35 degrees in summer.
They are a slow growing fish in the colder months, however they do gow quite quickly in the right enviroment.
As for importing, I don't know if this is available.
If it is, I would suggest to those who are thinking about getting one out of Australia to buy a huge tank, as releasing them into the wild over there is not a good thing. (this is how carp got into our waterways.)
Carp is one of australia's biggest vermin. It is illigal to relase them back into the water, even when dead as their eggs have a huge survival rate even if the carp is dead. I usually just leave them on the bank after cutting their throat. Or use them for bait for other types of fishing.
Cod, in my opinion would have to be one of the best tasting australian native fish, however due to increasing numbers, I only get to 1 a year.
As some-one else has suggested, golden perch is another great tasting australian native, some say that the goldens are almost as good cod, I doubt that.
Hope some of this info helps.
GooDoo knows a lot about australian natives, so I woudl take notice when he has something to say about them. I have learnt lots from him on other forums.
Hey! i have decided that i will stock my Semi above ground pond with Aussie natives!
It should house a few since it is 890 or something gallons.
Its going to have Murray Cod, Silver Perch, Golden Perch, Tandanus Catfish and maybe some aussie bass.
I cant wait, i start building in the next two weeks!!!!
It should house a few since it is 890 or something gallons.
Its going to have Murray Cod, Silver Perch, Golden Perch, Tandanus Catfish and maybe some aussie bass.
I cant wait, i start building in the next two weeks!!!!
Thanks guys. Glad you found the info interesting.
Realised I didn't touch on the Carp issue above... Yep, I hate Carp too. They have done massive damage to our inland rivers and I believe this damage has been seriously underestimated. All of the people who lived/fished/swam in our inland rivers said they were very clear with rich weed growth in summer and autumn (sometimes you could see the big cod swimming about!) and all of these people said this clear water and weed growth disappeared instantly when the Carp came in and has never really come back.
Certainly our inland rivers are permanently turbid today with little weed growth. And there are studies that show Carp DO destroy water weed and raise turbidity now.
All of this has massive implications for river productivity, functioning of river ecosystems and small native fish, which again I think most people including most scientists haven't thought about.
I suppose you could say in the simplest sense that millions of tons of biomass that should be taking the form of aquatic weed, biofilm, invertebrates and small native fish is now taking the form of millions of tons of Carp, and that has to be a bad thing.
Bloody Carp... Yep, it was a sad day when they got into our inland rivers.
Hopefully Daughterless Technology (look it up on the net) will allow us to get rid of them one day.
cheers
Simon
Realised I didn't touch on the Carp issue above... Yep, I hate Carp too. They have done massive damage to our inland rivers and I believe this damage has been seriously underestimated. All of the people who lived/fished/swam in our inland rivers said they were very clear with rich weed growth in summer and autumn (sometimes you could see the big cod swimming about!) and all of these people said this clear water and weed growth disappeared instantly when the Carp came in and has never really come back.
Certainly our inland rivers are permanently turbid today with little weed growth. And there are studies that show Carp DO destroy water weed and raise turbidity now.
All of this has massive implications for river productivity, functioning of river ecosystems and small native fish, which again I think most people including most scientists haven't thought about.
I suppose you could say in the simplest sense that millions of tons of biomass that should be taking the form of aquatic weed, biofilm, invertebrates and small native fish is now taking the form of millions of tons of Carp, and that has to be a bad thing.
Bloody Carp... Yep, it was a sad day when they got into our inland rivers.
Hopefully Daughterless Technology (look it up on the net) will allow us to get rid of them one day.
cheers
Simon
