Backyard Aquaponics
A place to discuss aquaponics

Depends if it is holding its breath

Oops, didnt mean to post that but anyhow

Oh, very quick there Ell!

Tony, sounds about right.

from memory if you have a high dissolved CO2 and saturation of CaCO3 then when the CO2 leaves the carbonate will drop out of solution...........

happens sometimes with planted aquariums, leaves get a powdery white film over them, i think its due to the CO2 being taken up at the leaf surface........

Obviously at PH8+ wer're talking about more than just calcium carbonates, prolly some bi-carbs too.

Sorry for the hi-jack brett.

I think marron are a bit different to yabbies in the ability to change colour.
My yabbie went blue after only two moults whereas my friends marron didn't change colour at all and he had it for well over a year?

i used to think they would always go blue in clean water. i know revise my statement to they will go blue if they are one of those freak blue marrons / yabbie.

their shell will incorporate the colour of the surrounding clay / silt, so if its a "bluey" then clean water should bring it out

Have not had a yabbie yet that hasn't turned blue in clean/clear water
Must be lucky I guess
Has anyone done any research as to why only some do it and not others

I thought the colour is caused by genetics. I wasnt planning on getting marron, but after seeing the parents, I couldnt help it. Its an incredible looking creature.

In some cases it may well be, but environmental changes still count for alot.
This maybe way of tap but in summer if i spent lots of time outdoors, my skin colour goes real dark, to the point of people asking if i have aboriginal descendants (mum who was the milkman )

the blue colour is a recessive gene. There is a yabbie farm near Anglesea here in Geelong. He breeds for that colour and charges a fortune to his asian customers. When he nets them, the ones with no blue go off to the bait shops. The blue ones go back into the water til they are an appropriate size.

Blue crayfish are raised here for the aquarium trade. Cost an arm and a leg, at least when they first came out. I was told that they were bred for the color.

All the adults I saw were blue and the tips of the claws on the tiny marron are blue so I hope for the best but expect them to taste great either way.

Anyhow, in the 18 months until then, has anyone tried this to grow marron;

Using 200L blue drums cut in half through the bung hole as normal and placing baskets made of mesh filled with hydrotron gravel so that the top 10cm of the half barrel is covered by gravel leaving up to 15 cm of water below. (200L blue drums have a radius of about 25cm) These drums would be set up as continuous flow (not flood and drain) and with plants in the gravel. Marron dont eat plant roots, do they? The hydrotron baskets should be light enough to lift and have dimensions to leave a gap for feeding which is covered in mesh to prevent escape.

Any comments?

that's an interesting idea Brett

I didn't end up trying the "marron under basket of gravel" thing.
The 25mm pipes connecting my blue barrel grow beds didnt allow water to flow fast enough and also tended to leak so ive moved the gravel into a hole in the ground lined with two layers of 200um builders plastic ($30 worth) and some spare shade cloth.

Unfortunately while moving the growbeds my second last marron (of originally 10) died and today the last marron died from the heat.
It was moving around this morning and was upside down by the early afternoon. Water test was NH4/NO2/NO3 all zero but sudden temperature increase to 28C.
Pics in memorandum (postmortem);