Just got some "ghost shrimp", any way to tell if they are Palaeomonetes patulous or Macrobrachium lanchesteri?

[sharrakor]

Hi,

I just got 10 "ghost shrimp" from Petsmart (the one near me is pretty good). But I'm pretty worried about whether or not these shrimp are the aggressive kind or not (Macrobrachium lanchesteri). Is there some way I can tell?

If it helps, I noticed that at one point, one of the shrimp seemed to grab on a newts tail with 2 claws, and the newt (a 4-4.5 inch N.v.v) just kind of swam an inch away with a flick of his tail and didn't do much else.

The shrimp are too large to be a food item for these newts, so the newts mostly ignore them; when a newt does approach a shrimp, the shrimp usually backs off.

Anyone able to help me here? I've searched, but im not sure how to tell the difference. I've heard a lot about not being able to tell the difference when they are young, but 7 of the 10 are berried, so maybe they are all mature?

 

[Ken Worthington]

Hi, I have half a dozen Ghost shrimp (Palaeomonetes or Palaemonetes, Google isn't sure!) which share a tank with my adult Spanish Ribbed newt (Pleurodeles waltl).
(To be honest, I've never come across the Macrobrachium that you mention.)
The newt and the shrimp get along fine (although the conversation may be a bit limited, I'd imagine).
I've never seen any aggressive behaviour from these shrimp.
If they get anywhere near the newt (and vice-versa), one flick of their tail and they dart away with incredible speed.
I believe the shrimp need slightly brackish water in which to breed (similar to a river estuary in their native habitat) and in the 18 months that I have had them I have never witnessed the 'patter of tiny claws'.
The shrimp are fascinating creatures in their own right.
Sometimes, if I cut a worm in half and drop it into the tank for the newt's breakfast, while Mr.Newt is munching away on the first half, one of the shrimp has grabbed hold of the other half and is trying to make a get-away with it.
From a distance this looks funny because you can only see the worm drifting across the tank and not the shrimp that's trying to claim it!

Anyway, I hope this is of some use to you, but like I say, I'm not familiar with the other type of shrimp you mention.

Best of luck, KW

 

[asfouts]

Hello,
I don't think that petsmart sells macrobrachium lanchesteri, but it may be possible that one slips into the batch? Petsmart can be inconsistent at identifying species.

I am not familiar with shrimp anatomy so I could be wrong. But it has more coloration in general. Ghost shrimp are usually colorless except for their red heart. Also Lanchesteri has iridescent black to dark green stripes down its head and can have patches of orange. I think the biggest identifier is the blackish stripes on the head and the green tint
You are probably right about maturation. I think they look almost identical when young, but lanchesteri gains color and stripes when older.

Also don't M. lanchesteri get rather large?
I think this picture might help of M. lanchesteri's head:
Macrobrachium lanchesteri

 

[sharrakor]

Thanks for the responses! I've been monitoring them today, and managed to snap a few pictures of them.

Based on the picture you provided of Macrobrachium lanchesteri, I think I probably have the "real" ghost shrimp, and not Macrobrachium lanchesteri. As far as the size goes, my non berried shrimp are all small, so I supposed it is possible that they are juveniles of either species, maybe? But I'm not 100% sure, so I thought I'd upload these pictures just in case anyone wants to take a look for themselves.

By the way, an autopsy of a female shrimp revealed a little bit of distinct red immediately above the claws (which were clear). Note that it was somewhat difficult to notice this without the aid of 30x magnification.

 

[sharrakor]

Not to self bump, but just a follow up. I just found this shrimp in here, with quite a bit of red in him at the base of the antenna and at the base of the claws (but much more pronounced than the autopsy on the female showed), and I'm not sure what to make of it. Ghost shrimp shouldn't have any red, other than the heart, right?

He is quite small; about 1/2 to 2/3 the size of the berried females.

 

[Linus]

I've seen some red coloration on Ghost shrimp before, though not often. This is normal.

Ghost .:. Glass .:. Grass Shrimp .:. Palaemonetes paludosus .:. Freshwater Aquarium Shrimp Species Information Page

Second pic shows a ghost with the coloration you're talking about.

 

[sharrakor]

I've seen some red coloration on Ghost shrimp before, though not often. This is normal.

Ghost .:. Glass .:. Grass Shrimp .:. Palaemonetes paludosus .:. Freshwater Aquarium Shrimp Species Information Page

Second pic shows a ghost with the coloration you're talking about.

I think this settles it. Thank you very much for putting my mind at ease!

 

[asfouts]

From the looks of it the green head is going to be the biggest sign other then behavior. I think if you notice any shrimp being too aggressive or is too large its most likely a lanchesteri. I was reading online also that getting a non-ghost shrimp in your batch is rather common. Sometimes the larger shrimp get mixed in like lanchesteri (probably because the little guys are meant to be eaten). So I guess if it gets too big and aggressive, get rid of it somehow. We also get cameroon prawns around here in pet shops. They look like ghost shrimp but 10X the size and are very territorial but usually if kept well fed will not attack fish.

Hope that helps.