how to tell M. Rosenbergii sex?

[BM]

My M. Rosenbergii is about 6 inches now (9"+ with arms), and still growing strong. It still molts about every other month (just molted last night). I was wondering if there is any distinctive way of telling its sex now that I can see its features better?

[Mustafa]

The males develop much longer blue chelae ("claws") and have a more gracile body.

[BM]

Do only males have blue chelaes? I noticed after the last molting, its entire arms went from a half length, deep dark blue to a full lenght bright baby blue, does that mean anything?

[prawnman88]

can u post some pics ? id sure like to see him im waiting for mine all i have in there right now is gupppies and a large bala shark

[badflash]

You need to get the bala shark out before the baby shrimp go it. The bala shark is much bigger than a guppy. The shrimp can fend off a guppy, but would be just a gulp for a big bala shark.

[prawnman88]

will do

[badflash]

Here are a few of my post-larval M. Rosenbergii.

They are just 1/2" to 3/4" long. I have maybe 20-30 left in my 40 gallon tank. This is all that is left of the 110 that were shipped and the 75 that arrived. If you get a bunch of these have your tank well prepared. They need lots of places to hide and like lots of verticle cling space like plants or breeding mops. If they molt and have no place to hide & harden up the others will eat them just for sport. It doesn't matter how well fed they are.

By the time they are fully grown there can be no more than 1 male and 2 females (3 total) in a 40 gallon tank.

They love moina and algae flakes. They don't really like the shrimp pellets. It is pretty funny to watch a 1/2" shrimp drive off a 1" guppy and take the food.

[prawnman88]

lol i liek when a fish comes over and a shrimp goes and pushes them away with there pinchers like there say no no no its mine lol

[Mustafa]

Very nice shrimp. The females are aggressive towards each other too by the way, so one of them might just eat the other right after molting, so your 1 male 2 female formula might just not work.

They love monia and algae flakes.

Just to clarify so people don't go searching for "monia," those waterfleas are actually called moina.

[prawnman88]

do they like live blood worms ? i know there small and they move whould they go after them no matter what size they are ?

[BM]

Sorry, no digital camera. I feed mine whatever I eat, eggs, hotdog, noodles, beef jerky, etc. I feed it like 3-4 times a day, and scoop out the left over. And everynight when i goto sleep i drop in an algae disc.

[chlorophyll]

Adult females usually have blue claws too, but they are clearly shorter than the males' claws. If your animal's claws only add 3 inches (outstretched) to a 6 inch body, I would say it's a female. OTOH, healthy females are usually ovulating regularly by that size, and you can't miss it when they have eggs, as unfertilized eggs will tend to stay under her tail for at least a couple days.

Here's a pic from http://www.fao.org/documents/show_cdr.a ... #P26_11006


And you can see how ridiculous the arms are on a male compared to females. You can also see how obvious new eggs are on a female. If you measure the claws in this normal stance, I can see how it might add just 3 iinches for males, but obviously their claws are much longer than that outstretched.

That page also shows you how to sex them by hand/examination, btw. But an isolated 6-inch (body only) individual is basically an adult and should be clearly sexable just by appearance, unless it's in the process of growing back damaged claws.

Also, I also use to feed mine kind of like you feed yours (BM), finding that they'll eat pretty much anything (hot dog, saimin, whatever... not too keen on some veggies like carrots though). Though the main diet was freeze dried tubifex. This particular individual was a female and would produce eggs after moults, as early as being just 4 or 4.5 inches in body length.

[Mustafa]

I have split some posts out of this thread and made a new thread called "Animal classifications, relations between invertebrates etc" as those posts were off-topic.

Mustafa
(with Admin hat)