Hello all.  Wondering if I can get some insight on an issue I've had with this species.  The backstory: I acquired a young male/female pair in September.  I soon lost the female.  Not wanting the male to be lonely and being intrigued by keeping this type of killi, I searched for and finally found a seller online selling two grown females; I say grown because the listing specifically stated that they were 20-22 months old.  I purchased them in mid-October, and have housed them in a 75 gallon tank with the male.  Up until a week or so ago, I was completely certain that they were both female, as they both had the same shape, little to no color, etc. and generally looked almost exactly the same, as it was hard to tell them apart.  However, one of them now sports male-like coloring and markings.  It seems really odd that it appeared female for over 2 months before suddenly showing it's true colors.  I initially wanted to blame the seller, but it seems like the seller may have been deceived as well.  Can anyone tell me if this is common? 

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Well that's definitely a pair.  It's not completely uncommon for sub-dominant males to show much less color and I could believe that it's possible to be so subdued that he would appear to be a female.  When the sub is no longer the sub the coloration can become apparent.  75 gallons is a pretty large tank for these guys so unless you are planning on breeding them naturally (ie. letting the fry grow up in the tank) you might find it difficult to collect eggs.  Good luck with the fish.

That's a great point.  I've heard of this happening with the scarlet badis (Dario dario), where the sub-dominant males dull their color to appear female and avoid harassment from the dominant male.

I am planning on breeding them naturally, or at least trying to, though I do plan on separating any fry I can find.

Thanks for the reply.

Ryan, you may have trouble getting these to spawn. Typically, these types of killifish want shallow water to spawn in: 3- 4inches. But there are ways around this.

My Nimbapanchax petersi were not spawning the 10 gallon tank unless I build a ledge in the aquarium about 3 inches from the surface on which I laid some mops. They then started spawning in the mops laying there with no eggs in the mops on the bottom of the tank or hanging mop.  Same story when I moved them to a 2.5 gallon tank. I put two bottom mops in the tank, one on top of the other. I only find eggs in the top mop and very few in the bottom mop. So, they prefer to spawn near the surface.

If you take a piece of styrofoam and tie a mop to it horizontally near or at the surface you may find the fish spawning there... but I wonder if they might be too skittish to rise to the surface of the water. Do you have a clump of plants in the the tank you can position the mops over so the fish are less afraid to enter shallow water?

Many killies seem to have sneaker males who look like females until they can become dominant but I have had female poliaki (which spawned!) turn into a male later in life (like swordtails do). I have not had several female N. furzeri females which I was very certain were females, begin to color-up like males late in life. I think killies do have the potential to change sex.

Bye

I've never found any fry in with my schmitti. I think the adults are very diligent about eating them and maybe eating the eggs too. I do get a few eggs in hanging mops, but have had poor luck with them hatching once removed. Not zero, but poor.

What has worked for me, albeit with low productivity, is keeping a pair in a tank with a LOT of floating (Ceratophyllum) and bottom (susswassertang or java moss) plants. Then I remove the adults after about two weeks. (Removing the plants instead would likely work about the same.) From then I put a little squirt of microworms in the tank every day. Soon, I will notice a few fry and then begin feeding bbs. Typically I get  about 6-10 juveniles this way.

The downsides to this method are that I tie up a 10 gallon tank for a long period and also that the sex ratio is skewed about 2-1 male. I assume that ratio is due to fry competition and males growing faster since, when I have managed to hatch picked eggs and raise in small containers, the sex skew has been worse.