Why Having Marron In Your Aquaponics System is a plus

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Marron are about the best tasting freshwater crayfish there is, and their benefits don’t stop at your tastebuds.

Marron (Cherax cainii) are superb eating and there is an argument that they taste even better out of an aquaponics system. Less Muddy tasting.

Marron bought at fish markets or on the menu at a restaurant have been farmed in dams, which are a muddy environment. Whilst marron are purged (left in clean water tanks for a few days without food to work the muddiness out of their system) they commonly still have an ‘earthy’ taste to them. Some people like that, like me, but, in an aquaponics system, there is no mud, no sand or silt so you will taste the pure flavour without that hint of Earthiness.

Within the aquaponics system marron have proven benefits like, Stirring up the bottom.

Marron contributes to the aquaponic ecosystem by stirring up the bottom of the tank and eating uneaten fish feeds and other organic material that sinks to the bottom of the tank.

Even with your pump draining back to the system, and air tubes, your aquaponics tank is likely to have ‘dead spots’ or areas where the flow of water is poor. These areas can see a build-up of organic matters potentially contributing to poor water quality. The movement of marron through these areas stirs up this material and increases the chances of it being picked up and pumped into your grow bed (or solids filter).



Overfeeding fish is one of the leading causes of poor water quality in an aquaponics system and it’s not always because you fed them too much. Sometimes the fish aren’t hungry and other times they will take the feed, only to spit it out under water. In both cases you aren’t going to be able to scoop out all the uneaten feed. Marron is your insurance policy to make sure that feed sitting on the bottom of the fish tank isn’t going to build into a problem. I use FLOATING and SEMI SINKING feed.

But, there are also some things to think about when adding Marron to your system. Marron taste so good that even other marron think they taste good too. Marron eating each other is very common in an enclosed environment and here are a couple of tips to help you avoid disappointment and finding half eaten Marron you should be eating.


Don’t have more than one marron per square metre of fish tank. Any more than that and you will run into problems.


Marron grow by shedding their hard shell (moulting) and slowly hardening the soft shell that had developed underneath. 90mm PVC piping must be added to the tank to give marron the ability to hide, especially when they are soft shelled after a moult. A couple of marron will coexist in the same fish tank however there is an increased risk of attack during a moult. This is not only a territorial thing but also a survival of the fittest move.


One method to increase stocking density while decreasing chances of cannibalism is to break off the top closing pincer on each claw. Although the claw will slowly grow back (meaning you will need to do it again) it needs to be mentioned that marron are very shy and sensitive creatures. Although the act of breaking off the pincer doesn’t harm the marron, the stress caused will lead to losses. This is something that I do not do myself, but I have seen it done in huge stocking dams and tanks down south.

Tips for buying

Marron can be bought very easily in Western Australia. They are expensive in aquarium shops and less expensive at places that sell large numbers of koi, although the marron are likely to be quiet small here. Marron can be bought live at fish markets and you can order direct from marron farms, however most marron farms will have a minimum order of about 5kg. Try finding other types of Marron, like, Hairy Marron (Cherax tenuimanus), the common Smooth Marron (Cherax cainii) and the infamous Blue Marron.

For people outside of Western Australia, the same concept works for Yabbies. Although smaller than marron, yabbies are far more aggressive and increase the probability of cannibalism.

Barbecued Marron with Garlic & Herb Butter

Just reading this menu title makes me drool! However, marron are an important contributor in aquaponic ecosystems and should be considered heavily.



*You will need some Jarrah, Marri, or any Native Hardwood to be burnt slowly down to create embers and coals. White hot embers and coal is what we are looking for, not red hot glowing burning or still smoking is best.

Kill the live marron by running a sharp spike directly into the brain just behind the eyes (ike-jime method  it also known as), which is the most humane method. Once they have demised, grab a sharp long kitchen knife and split longitudinally from the Head, through the Thorax, down the Abdomen and on to the Tail. Place on the grill shell-side down, and season with sea salt. Grill over the embers for approximately 3 minutes.

Meanwhile, grill the Asparagus spears, and prepare the Salad (whatever your choice). Cut in half the finger limes and Lemon until the essential oils are released. You should be able to smell this from across the yard.

Remove the marron and drizzle with some Garlic and Herb Butter (I like to use Native Rosemary, Native Thyme and Native Oregano, Lemon grass sometimes too), or a minute or two before finished, add the herb butter to finish off the cook.

Garnish with the native herbs and serve immediately.

Big Up to our TO’S and Ancestor’s trodding here long before Colonization and will be here long after. Give thanks for life!