Hi guys,
I was at a Clarias gariepinus inland catfish farm the other day.
Don’t start – I wish I had my camera
!
I was amazed at the filtration systems...
Lots of fast moving water for oxygenation (more for bacterial reasons I suppose) and big water change capabilities.
The fry are reared in tanks much like ours. Huge females in large 200gal tanks are injected with egg producing artificial hormone (pituitary extract) and have their eggs collected.Males had their milt extracted.
Fertilezed eggs are held on screens at an angle for fry to fall from when hatched (this is well documented online).
Anyway, I digress.
My points are that
i) I was amazed at the sheer absence of mechanical filtration
ii) I was surprised at the method of biological filtration.
The farm uses sedimentation to remove solid waste from the catfish’s living space, but not from the water. Water passes into neighbouring tanks and cisterns where it collides with obstacles depositing the solid waste.
Water changes are used to reduce ammonia, nitrite and nitrate although biological filtration is present.
The water is pumped perhaps 10’ - 15’ into the air and allowed to run down a high surface area tower much like a car radiator or a heat sink (or koi tower). This happens outdoors in the sunlight and algae is cleaned off the structure regularly. Biological filtration occurs by adsorption on the tower surface and a portion of nitrogenous waste is removed from the system.
Why don't we use this sedimentation process more in aquaria?
Is it only because it takes up so much space?
What about our monster tanks and huge ponds that we can't realistically filter diatomically or ultravioletly. It must be so much more economical.
Can these not support this space requirement for sedimentation?
All the water I saw was crystal clear.
We should also try to use refugia and algae growth traps more, these are always the first threads I am drawn to when searching through new posts. It seemed, and seems, so sustainable, so zen.
What are your thoughts ?
I was at a Clarias gariepinus inland catfish farm the other day.
Don’t start – I wish I had my camera
!I was amazed at the filtration systems...
Lots of fast moving water for oxygenation (more for bacterial reasons I suppose) and big water change capabilities.
The fry are reared in tanks much like ours. Huge females in large 200gal tanks are injected with egg producing artificial hormone (pituitary extract) and have their eggs collected.Males had their milt extracted.
Fertilezed eggs are held on screens at an angle for fry to fall from when hatched (this is well documented online).
Anyway, I digress.
My points are that
i) I was amazed at the sheer absence of mechanical filtration
ii) I was surprised at the method of biological filtration.
The farm uses sedimentation to remove solid waste from the catfish’s living space, but not from the water. Water passes into neighbouring tanks and cisterns where it collides with obstacles depositing the solid waste.
Water changes are used to reduce ammonia, nitrite and nitrate although biological filtration is present.
The water is pumped perhaps 10’ - 15’ into the air and allowed to run down a high surface area tower much like a car radiator or a heat sink (or koi tower). This happens outdoors in the sunlight and algae is cleaned off the structure regularly. Biological filtration occurs by adsorption on the tower surface and a portion of nitrogenous waste is removed from the system.
Why don't we use this sedimentation process more in aquaria?
Is it only because it takes up so much space?
What about our monster tanks and huge ponds that we can't realistically filter diatomically or ultravioletly. It must be so much more economical.
Can these not support this space requirement for sedimentation?
All the water I saw was crystal clear.
We should also try to use refugia and algae growth traps more, these are always the first threads I am drawn to when searching through new posts. It seemed, and seems, so sustainable, so zen.
What are your thoughts ?
