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Saturday, February 14, 2009

Malaysian Fresh Water Grass shrimp.(Palaeomonetes)

Other common names include ghost or glass shrimp, usually seen in aquarist shops sold as bait food for large fish or in lakes, rivers and jungle streams. I have observed in the past that fish fed with Grass shrimps have their natural colors enhanced and this I found out is due to carotenes in the shrimp, evident when they die by turning pink.
The jungle stream where the two specimens shown below were caught.
My favorite activity when I take an occasional dip in jungle streams to cool myself down is to look out for grass shrimps that can be found hiding in rock crevices or beneath rotting wood and vegetation by snorkeling under water (if it is deep enough).

For years I have often wondered about the difference in shrimps and prawns and it appears there are no clear definitions described and it can vary from nation to nation which causes more confusion, like most layman I have used this two descriptions interchangeably without problems, it most probably boils down to the receiving end having the same problem.

So what is the actual difference? Shrimps and prawns are closely related, both are crustaceans.
Crustaceans are creatures that have primarily adapted to life in the oceans and have a hard shell with mandibles to handle and consume food. Lobsters, shrimp, barnacles and crabs are examples of crustaceans. If we were to go one step up, they are arthropods but let’s not even go there. It seems even wood lice are crustaceans to confuse us mere mortals more.

For many, the descriptions are that prawns are larger, while shrimp are smaller is generally accepted but is technically wrong. Shrimp and prawns are from different suborders. Prawns are in the suborder Dendobranchiata, while shrimp are classified as Pleocyemata. The differences lies in the gill structure, front pincers and leg length, subtle differences indicating deviating steps taken along the evolutionary path and other boring biological stuff.

Grass shrimp with their almost transparent body blends in well with the environment where they can be found, it helps them to survive from predators, camouflaging has always been nature’s way of defense, even though it is known to be an important food source for many predators lurking nearby, mostly fish. No doubt their small size, not exceeding 1.5 inches helps, females are larger.
Still find it hard to tell whether it is a prawn or a shrimp? Stop fretting, you are not alone.
If you want a full time cleaning crew in your aquarium put some grass shrimp in and you will see that they are also excellent scavengers, eating any left over your fish can’t finish. In fact, because of their translucent body, you can actually see what they have just eaten or clean up. If you chance upon an egg bearing grass shrimp it is even more intriguing, eggs or live baby shrimps can be seen under their swimmerets or swimming legs if you may.

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