Crayfish

[Noah Howard]

Hello Folks!

    So, I have done a little bit of research and I am interested in getting Crayfish for my Aquaponic systems. I have A TON of room in my beds to be able to have crayfish. I am not experienced with crayfish at all beyond my childhood. I would like to maybe hear some pros and cons from those of you who do have experience! Any information is helpful!

[Steve R]

The key points to crayfish in aquaponics is water quality, species,  and den space. To get the most in a given space cut a bunch of 2 or 3 inch ling 1' pvc pipe and toss it in the bottom of where ever your keeping them. If they each have there own den they fight alot less. The best kind to get are the self cloning ones because they can put out hundreds or thousands of babys with out the need to breed. The biggest reason people start losing eggs and losing crayfish is water quality. Like salt water inverts crayfish need certain levels of calcium magnesium and alkalinity to properly form and maintain there exoskeleton and eggs. You want your KH to be in the 4 dkh - 10 dkh range or 80ppm - 300ppm. You want your calcium to be in the 20 - 50 ppm range can be a little higher and be safe.  And your magnesium at 15 - 45 ppm for optimal grown of fresh water inverts. It will also keep your water stable PH wise but that is an entirely other discussion. I have a few thousand fresh water shrimp at home of various species. 

[Pat James]

Steve, I have 38 pieces of PVC that are bundled and stacked like a honeycomb so they don;t take up too much floorspace on the undergravel filter. I give them 4 or 5 extra strength tums a week after I do a partial water change. Their replacement water comes from my AP system and is allowed to warm to room temp before adding. I am feeding them algae/food detritus from my raft beds as that is what they will be living on once released. I have a dim light on the aquarium. I also added a few chicken and fish bones for them to gnaw on and to possibly release a little calcium and phosphorus.I even threw in a handful of red worms to eat stuff down in the gravel.

I was just surprised at the difference in size as these were all from the same source living in the same environment. I'm a little unwilling to set up a second aquarium but I might so I can maintain a couple of the larger crays as "brood mares" under controlled circumstances.

[Steve R]

One last note you can not keep crayfish in a hydrates based system they will either die when they molt or sooner. 

[Pat James]

Steve.....What is a hydrates based system?

[Pat James]

Just measured one of my marmorkrebs (marbled crayfish). that held still against the front glass of the aquarium. It measured 2 3/4 inches. I now have 4 survivors... at least a few days ago, I could see 4 individuals at one time.

[Keith Rowan]

with crayfish, you should supplement with iodide.. used in marine aquariums to provide iodine which the shelled animals need... add half the amount recommended for marine aquariums

[David - WI]

Dammit... every time you post something it costs me $25!  LOL

Keith Rowan said:

with crayfish, you should supplement with iodide.. used in marine aquariums to provide iodine which the shelled animals need... add half the amount recommended for marine aquariums

[Keith Rowan]

glad i could help.. hehehe

[David - WI]

I do appreciate the info!

Keith Rowan said:

glad i could help.. hehehe

[Chris Duke]

I wonder if the crays would be inclined to eat your goldfish? Or the other way around? Be sure to give them plenty of hiding places so they don't feel the need to go all territorial on each other. I'm planning on doing a natural style outdoor pond with crays and also stocking it with fish. I figure so long as they have room, they should keep each others populations in check. I'll also be trying to raise crays in the indoor sumps in the greenhouses. I can't wait to get started.

[Carey Ma]

I don't know if he still visits this site but Chi Ma use to be our crawdad guru.

I raise crawfish but in pond culture so not really applicable to your situation.

Cheers, good luck and have fun!

[Pat James]

I just transferred 2 of my 3 surviving marbled crays to a second aquarium. Last night I observed a bunch of tiny crays in the main tank. no telling  how many are there but some are almost  1/2 inch so they must have hatched a few weeks ago. The third cray still has berries under her tail so I left her in the main tank. I set up the second  aquarium with a new power filter for the adults.