Backyard Aquaponics
A place to discuss aquaponics

i was wondering if neone has like crawfish or crabs in their tank to eat dead fish, or if there are any creatures that would eat some of the solids left in the tank, i want to maximize the power of using fish or whatever to keep the fish tank clean, i understand that the bacteria keep the water clean but there is still the solid fish waste and like left over food i feel that removing this is taking somthings away from the system, and another question is would my system do better with alot of smaller fish eating like veggies or pellits or should i go toward less bigger fish and feed them smaller fish, would't this add different minerals to the system or maby in different ratios. sorry for all the questions but i am wondering how far to people take the whole miny ecosystem

yabbies are popular, but the fish eat the yabbies.

Crawfish = yabbys
Have not hear of people using crab tho...
I have 2 yabby in with a tank filled with guppies, swordtails and goldfish and it works well enough...
Snails eat a lot od the fish waste too

Fish eat the crayfish and vice versa depending on size and breed but one thing i have seen is the minuite the crayfish moults Lookout!! if the fish can get to it theyll destroy it as its shell takes a while to harden.Eiher seperate tanks or a false bottom for the crays in the fish tank( could be a bit of a pain to access the crays though).

Heaps of dwv/pvc off cuts at the bottom of the tank helps too

I think a sequential tank set up would work, with a return from the grow beds to the fish tank, and from there a flow to the yabbie tank, and a return up to the grow beds. You could place the fish guts into the yabbie tank for them to eat and nutrient cycle that back into the system.

We have freshwater crabs here, too.... maybe a yabbie/crab tank?

It does work as that is my setup at the moment and when I get more yabbies I will remove the guppies so it is purely a redclaw tank (or leave them in and they become yabby food )

Aquamad, as my sstepmum says, "great minds think alike"....

Hi rblaster

Freshwater crabs can be found here in NZ as well, perhaps your local Aquarium would know more. The forum has looked at molluscs a fair bit (snails, frehwater mussels etc) but they have their own problems.

Snails crawl up pipes, grow, and block things, the water snails will actually live and breed in your gravel beds too so I've found making my myth of goldfish culling them all just that - a myth.

Mussels, as part of their life cycle, attach themselves to the gills of fish, this has been known to kill some fish and could be a serious issue in an enclosed system.

Freshwater crays (yabbie, koura, crawfish) certainly seem the best option to me so far as utilising in-system wastes. It's entirely possible to raise a polycultureas many members here are doing so as I write. As Aquamad said, lots of pipe etc, places for them to hide from the fish.

My problem is the local salmonids I have are slender, carnivorous, and can fit anywhere a koura (kiwi crawfish) can. I think it's possible to enclose them in mesh cages on the base of a tank, thereby having them seperate, but doing their job.

hi AA, nice to hear from you again - just heard the kiwi tennis team is making a name for themselves

what exactly do the crawfish "yabbies" eat?

Whatever the fish don't eat the yabbies will eat. They are essentially bottom feeders and will munch on dead and decaying matter on the bottom of the tank. For a treat you can give them special growing pellets or freshly steam veges... not kidding! Mine are feed peas and carrot.

i dropped a piece of steamed carrot in the indoor tank last night, took the yabbie about 4 seconds to come rushing out of hid hidy hole pvc pipe on the other end of the tank. he spent the next 30 mins waling around with it in once claw like a pizza, while eating it

LOL!!!!

Thats so cool Steve, I can just imagine it!

Yabby, carrot pizza.....Hehehehe