Sexing dwarf crayfish?

ToddnBecka · Post by **ToddnBecka** » Sat Nov 04, 2006 10:12 am

I just netted the 3 orange/brown mix to move them into the 30, and can't see any differences between them. Am I missing something, or could all 3 be females? What specifically should I be looking for? They were sold as 1m/2f, and are definitely large enough to breed.

Neonshrimp · Post by **Neonshrimp** » Sat Nov 04, 2006 10:28 am

Here is a thread on sexing cajons:

viewtopic.php?t=1663

ToddnBecka · Post by **ToddnBecka** » Sat Nov 04, 2006 11:01 am

Thanks for the link, I'm assuming all crayfish are similar as far as anatomy? I looked closely at all 3 while they were in clear plastic cups, none have the smaller extra pair of legs. Looks like I'll have to wait for the oranges to grow a bit before I'll have any hope of breeding. I just received 4 (hopefully 2 pairs

) from Germany, and they're all younger ones, the largest about half the size of the largest mixed female. Being smaller, I placed them in the 10 with the cherry shrimp to grow a bit. What size do they need to be for breeding?

FISH WORLD ERIE · Post by **FISH WORLD ERIE** » Sat Nov 04, 2006 10:25 pm

About 1 inch in size to breed and you should be able to sex them at 1/2 to 3/4 of an inch. You will have to physically pick them up and roll them over.
Sexing them by looking through something is pretty hard. When they are mature males tend to have bigger longer claws and females tend to look heavier in the tail. The dwarfs and american species are sexable in the same way. Australian crayfish play by different rules. Good luck with your crays.

Jason

Neonshrimp · Post by **Neonshrimp** » Sat Nov 04, 2006 11:36 pm

Australian crayfish play by different rules.

Jason, is it a more complicated set of rules or just some other area of the body?

FISH WORLD ERIE · Post by **FISH WORLD ERIE** » Sun Nov 05, 2006 6:28 am

Australian males do not have the gonopods or extra set of legs. The female will have her genital openings "little circles" on her third pair of walking legs. Males will not have anything I know of. These crays I am not sure at what size they are sexable but I would guess 2 1/2 inch. I have only sexed older 3 + inch specimens.

jason

YuccaPatrol · Post by **YuccaPatrol** » Mon Nov 06, 2006 12:34 pm

I was just looking at my Cambarellus diminutus females that I have isolated in some of those clear plastic guppy breeder boxes.

I noticed that when I looked at them from the underside, I could see the annulus ventralis as a dark spot right between the last set of walking legs. The a.v. is about the size of a grain of sand and very obvious against the pale underside of the female crayfish.

Assuming that this structure is colored in other species of Cambarellus, this should be an easy way to identify a female without any additional magnification.

I'd suggest putting the crayfish in a clear bottomed container and you should be able to sex them without disturbing them very much.

since C. diminutis is the smallest species in this genus, the a.v. should be even easier to see on larger specimens.

Hope this helps!

badflash · Post by **badflash** » Sat Nov 18, 2006 11:14 am

This is the easiiest way to sex them:

I was cleaning out one of my aquariums that my Wild cajuns were in and once I pulled out the overgrowth these two found each other. First time I've seen it personally.

YuccaPatrol · Post by **YuccaPatrol** » Sat Nov 18, 2006 11:15 am

Nice photo, badflash!

I've been watching mine do the same thing, but they always seem to want to do it in a corner of the tank where I cannot get a good photo. . .

Neonshrimp · Post by **Neonshrimp** » Sat Nov 18, 2006 11:17 am

So which is which? Who is on top/bottom?

Thanks

!

Neonshrimp · Post by **Neonshrimp** » Sat Nov 18, 2006 11:47 am

I see now, the male is the one on top

Thanks for the picture!

badflash · Post by **badflash** » Sat Nov 18, 2006 1:32 pm

Neonshrimp wrote:I see now, the male is the one on top Thanks for the picture!

I think that is always the way they do it. Not much imagination in crayfish

CanadianCray · Post by **CanadianCray** » Sat Nov 18, 2006 7:14 pm

The male is always the crayfish thats holding the others claws as they are always the ones that initiate the mating.

badflash · Post by **badflash** » Sat Nov 18, 2006 8:31 pm

CanadianCray wrote:The male is always the crayfish thats holding the others claws as they are always the ones that initiate the mating.

Boy, that sounds familiar....

I guess that would explain my 1 clawed females. He must get carried away.

ToddnBecka · Post by **ToddnBecka** » Sun Nov 19, 2006 12:02 am

Very nice pic. Looks like he didn't buy the "headache" story...