Paratya Australiensis?

[mr_c265]

First a bit of background.

My Dad has a property on the fish river at Tarana (20k's from Oberon NSW), he has a backwater (seperated from the river) which we often catch things from to put in his native tank. These are photos out of the tank.

There are 2 species of shrimp that we find. There is one with long arms, i assume a Machrobrachium of some description, i dont have a photo so happy to leave that one alone. The other one appears to be Paratya Australiensis, however, there are a few things that make me question this,

1. The pond gets frozen all over the top in Winter and in the Summer, the ambient temperature can easily reach over 40 degrees.

2. It has markings that i don't see usually on Paratya Australiensis

3. I have caught them around 6cm (the photo is of one 6cm long), which seems a bit large for Paratya Australiensis

I admit, at one point when the river flooded there were small clear shrimp (nearly 100% sure Paratya Australiensis) in there and we had never caught a large one like i am describing now until this year, but since its been quite dry lately and we had a flood just before the dry spell, we have been finding these larger ones. There have been shrimp in there for at least the last 6 years and we did get up to 50 (and they were little) in one scoop, especially when theres been a bit of rain, at the moment and only this year we are only getting around 3 of these huge ones out of the Valis beds with every scoop.

Does this look like Paratya Australiensis still?

[northboy]

Hi

Paratya are extremely variable in there range and the occur in a very large part of Australia, colour is never a way of identifying an Australian shrimp as across a shrimps range and with in drainage's they can be different.

Have a look at the shrimps nose or rostrum, that is the first and easiest reference to start with, then you have start to look at the feeder feet, then swimmers, you get the point LOL.

In the right situation most shrimp will grow much bigger than the science papers say, because they have food laid on and few predators. Most size guides are a average across the range.

The interesting thing with Paratya is the colour variation across the range, on the Atherton table lands we have white spotted ones, red striped ones and I was shown some red and black spotted ones last week. Also a lot of shrimp change there colour and pattern during the life and size range. Try to get a clear shot of the nose.

The only sure way to ID them is by killing a few and looking under a microscope and or doing the DNA on them.

Looking at photo it looks right for a Paratya

Bob

[mr_c265]

Thank you for that! Ill try to get a few brought down to me in Sydney, hopefully they survive the trip this time, and i should be able to get some better photos. Very cool about the colour morphs, i suspect it is a Paratya Australiensis now also. id like to try and breed some of the dark green coloured ones i found (if dad gets them down to me alive), hopefully i should have some photos soon.

[northboy]

Keep the ambition to breed some thing different, that is how it started years ago in Asia with all the colour varieties of Cherry and Crystal we have now and I would love to see an Aussie shrimp be fashionable and have lots of different colours, it is very possible and doable.

Bob