breeding colubian shark

Question
We have three Columbian Sharks.  The other day we observed one of them "standing" in the bottom swishing her tail. We say "her" because an oil like substance exited her lower portion.  The following day the other two sharks had a ball like protrusion in their jaws.  After studying the  internet we understand that the males are incubating the eggs.  When will the eggs hatch? What should we do to protect the young from the parents who obviously are carnivores?  Thanks,  Audrey

Answer
Hi Audrey,
  I figured out the problem.  "Columbian shark" is one of those
terrible names that really doesn't describe the fish.   
The fish you have is a brackish water catfish, Arius seemani.
And you are right, they are male mouthbrooders.  So that is
very cool that the males are incubating.  I have no idea how long
they will take.  It depends on water temperature and egg size.  
I will be VERY interested to know what happens.  

 I trust that you know that you have to be very careful around these fishes because you can get "stung" by their spines.  My guess is
that mouthbrooding males will be particularly edgy.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>


Hi Audrey,
  Hmmm.... I'm not so sure that is what is going on.

  When you say "Columbian shark", I am trying to figure out which fish you are talking about.  I assume it is one of the tetras.  However, there are no mouthbrooding tetras and certainly no male mouthbrooding tetras.

  Is there any chance you could send me a photo of the fish and/or perhaps one of the websites where you got some of the info from and I can help sort this out.  

-- Ron Coleman
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>