Macrobrachium Dux with eggs.

Nion · Post by **Nion** » Mon Sep 19, 2005 9:56 am

I have a lone Dux female with eggs. Just noticed them this morning, she usually stays hidden so I don't know how long they have been there.
She has not had any companions for about a month, they died a week or 2 after arrival.

What are the chances that these eggs are viable?
What color are fertile eggs?

Anyone here have any experience with this type of shrimp?

Thanks,

Nion

Post by **Mustafa** » Mon Sep 19, 2005 10:48 am

If there are no males then the eggs are not fertile and will be dropped soon. The only way the eggs might have been fertilized is if she has been carrying those eggs for a month or more and one of your males mated with the female before he died. That's highly unlikely though, since this shrimp species should not be carrying their eggs for that long. The eggs are very small and there should be hundreds of them I assume, correct? I have not had personal experience with this species yet.

By the way...I highly doubt that the real scientific name is Macrobrachium dux. It's just imported under that name from Africa.

As to the color of the eggs...that's not always all that reliable of an indicator for fertility. Many species' eggs have the same color in the beginning no matter if they are fertile or not. Only later, as the embryo develops (or not) will you see color differences.

Nion · Post by **Nion** » Mon Sep 19, 2005 11:15 am

How small is small when you are talking about eggs?

These don't appear very small, and there definitely aren't hundreds of them.

Post by **Mustafa** » Mon Sep 19, 2005 11:34 am

Small eggs for a medium sized Macrobrachium look smaller than Red Cherry Eggs. The species with large eggs and abbreviated or suppressed larval development (= mini shrimp hatching) have larger eggs than a Red Cherry. If you count less then 100 eggs, chances are that this species is of the abbreviated or suppressed larval development type.

Hmm...now I'm really interested to find this out myself...do you happen to have a picture or could take one with the eggs more or less visible in the pic?

GunmetalBlue · Post by **GunmetalBlue** » Mon Sep 19, 2005 12:26 pm

Hi Nion, here's a link from Crusta 10; it wasn't stated as being pregnant, but it seems to show the female with very small eggs that seem to number in the hundred(s). Do you think this is the species you have?

http://www.crusta10.de/userimages/Macro ... %20fem.JPG

I have a feeling that if your shrimp's eggs aren't that small nor number in the hundred(s), you may not have a Dux (I think that's what Mustafa was saying). Certainly a picture of your shrimp may help.

-GB

PS: This is a moot point, as it's already been mentioned that it's unlikely the eggs are fertile, but if you happened to have noticed her molted exoskeleton recently, it's usually within a couple days afterward that the eggs appear. So you'd be able to guesstimate about how long the eggs were there.

Nion · Post by **Nion** » Mon Sep 19, 2005 3:05 pm

All I have is a point and shoot digital so my pics are really horrible. You can kind of make out the eggs.

http://wackyonline.com/fish/061.jpg

http://wackyonline.com/fish/039.jpg

Nion · Post by **Nion** » Mon Sep 19, 2005 3:08 pm

This is the pic that the seller had.

Post by **Mustafa** » Mon Sep 19, 2005 3:17 pm

Thanks for the pics. Hmm...although it's hard to tell the eggs do look like they are pretty large on the pics. That would mean that the shrimp species you have most likely produces mini-shrimp or very large, advanced larvae (like Palaemonetes paludosus whose eggs are very large also). So, what's your estimation since you are the only one who can see the eggs up close? Does it approximately look like there are less than 100 eggs? Also, do you happen to have a picture of the males before they died? If not...did they have really large chelae (arms) or just a tad longr than the females'?

Nion · Post by **Nion** » Mon Sep 19, 2005 4:26 pm

There are far fewer than a hundred eggs, probably closer to 20 or so.

The males claws were very much larger and darker than the females.

Post by **Mustafa** » Tue Sep 20, 2005 10:11 am

Thanks.

Nion · Post by **Nion** » Tue Sep 20, 2005 1:06 pm

Should I isolate her and see if the eggs hatch?
What would be the best environment?

Nion

Post by **Mustafa** » Tue Sep 20, 2005 4:30 pm

As I said, it's highly unlikely that the eggs will hatch. I would wait a week or two and see if she still has the eggs by then. If she does, then you can either leave her in the tank if there are no fish in the tank or put her in a cycled 10 gallon tank with lots of plants or other hiding spaces all by herself. It takes 38 days for my Macrobrachium assamense/dayanum babies to hatch and they are of similar size to your Macrobrachium. So, if the eggs last that long, then they are most likely fertile and you might see some offspring.

Nion · Post by **Nion** » Tue Sep 20, 2005 5:58 pm

Cool, I'll keep a close watch on her the next few weeks.

Thanks for all the help.

Post by **Mustafa** » Tue Sep 20, 2005 6:19 pm

You're welcome.

Please keep us updated on this.

Nion · Post by **Nion** » Fri Sep 23, 2005 2:30 pm

Bad news...

Last night before bed I noticed that she was not caring the eggs anymore and this afternoon when I got home from work she was dead.
I have no idea what could have happened to her.