RCS question

[DD7687]

I have 10 RCS in my tank. Most of them have developed a yellow patch on their back right behind their head. At first I thought it may be the egg sack. But, today I noticed the same yellow part on one one of the male shrimp. Now I'm not sure what it is. Anyone have any insight on this?

 

[ArtistGardener]

A saddle is something a shrimp develops before she is ready to carry eggs. The lower photo may be a less colorful female rather than a male. My 20 gallon tank currently has over 20 RCS in it (reproducing like crazy!), and they look like yours with the saddle on their backs.

 

[DD7687]

Thanks!

 

[PerfectDepth]

+1 Those are females in both photos, showing their "saddles".

You can't really go by color when determining sex. The shape of the underside of the tail is the best way to tell in my experience. Take a close look at the side-view of the tail on one of the shrimp without a saddle for comparison. Males' tails are straight, or even concave, while the females' tails are convex.