First Pure ( big spot) Black Diamond SA bred pups!!

Thank you @Ebrahim

 

@Whoknows , i dont mind the discussion on the thread, after all its all relevant to ray keeping so its good info for anyone reading through the thread.

As a matter of interest, i just checked with Cesar as well and he is running 12000l Koi pond pumps in his two tanks on one 50mm hole
He is determined he can pump up to probably 19/20000l liter on one 50mm hole, providing your sump is big enough to handle that volume of water going in
The compartment where the water goes in has to be big enough to handle the volume of water that comes into the sump at those high flow rates

 

I actually covered this both in a conference and in discussions with the bosses in our filtration design, all quite recently funnily enough...

It all has to do with their marine ancestry and how they had to adapt to become freshwater animals. Short bit of elasmobranch anatomy/physiology: the majority (i.e.: marine) species retain metabolic salts, including urea (and some ammonia). They do this to have the "same" amount of salt inside their body as their external environment (anyone remembering principles of osmosis from biology?). This process is a means of osmoregulation (or rather osmoconformity) - meaning minimal salts/ions are lost to, or taken up from, the environment.

However a few million years ago, some rays decided to become permanent freshwater dwellers. The evolutionary pathway taken lead to them no longer holding onto these salts, especially since it is so unnecessary in the Amazon where the water is extremely ion/salt deficient. So instead keeping these internally, they're almost entirely flushed out of their system.

Surely this is no different to bony fishes? Not quite, although I will admit I haven't researched this aspect extensively and don't know how far along the physiology guys have looked into this. From what I do understand, it that most bony fish actually do some amount of ammonia in their blood; conversely, (these particular) freshwater stingrays have completely lost the ability to retain and resorb urea/ammonia. Again, on the research side, I cannot give numbers to say that per body weight that stingrays definitively excrete greater nitrogenous wastes than other fish of comparable weight, but given the mechanisms of how these animals manage their metabolic wastes, it does make sense. Being carnivores, high nitrogen output was always going to be an issue to consider anyways.

I will need to hit the books again to give you a more solid answer, but that's the jist of it.

 

@SalmonAfrica ...
Thanks so much for the comprehensive explanation... much appreciated
I think it will certainly give everyone a better understanding on why the filtration is so important on ray tanks
I think if people understand the reasons why it makes it much easier to care for them

 

This is very interesting to read! Funny enough animal physiology was what got me into wanting to start keeping fish in the first place (I've always wanted to but this subject gave me that nudge that got me to actually do it) because I find it so fascinating how fish of all kinds need to regulate themselves according to their environments, such as saltwater vs freshwater and the ions and salts involved.
It's just so fascinating!

 

Yes... both his tanks are 4000l each excluding sump

 

Its also a little while since i updated this thread

Pups are now all together, Polkadots. Pretty Face and Blacky's

Some have gone to their new homes but i let them go already as they were going to people that are experienced fish keepers and have had rays for a little while like @top dog
These will be going in the coming two weeks except for the two little ones of blacky which are younger and will stay a little longer

Excuse the algae on the bottom but try not to put the little noses out of joint too much

 

Absolutely awesome Maria.. Stunning fish

 

all growing so nicely
will post a few update pictures of ravioli soon

 

Thank you @Adam K

 

Thanks @Reedfish

Hahha next time you come over we will put one in a little cooler bag or you!!

 

Thanks @top dog

The two tiny brats are adorable!