"Long Armed Prawn" @ Petco = Macrobrachium?

[YourPalCM]

Hello everyone,

I was at Petco today and they had something called a "Long-Armed Prawn". By searching the internet, I gather that these are "Macrobrachium."

However, I also gather that there are many types of Macrobrachium.

1) Does anyone know what kind of Macrobrachium Petco is selling? The two girls working there were of no help.

2) How big do these things generally get? (I know that might be tough to answer without knowing the exact type.)

3) I read that they are omnivorous. I have a planted tank - do they do any damage to plants?

4) I read that they are "nippers" but fine with larger fish. I have a 46 gallon tank with a 3 Dwarf Gouramis, a pair of Angels and 6 Rummy Nose Tetras. I also have a Wood Shrimp in the tank, a few Corys and a Pleco. Would the Tetras, Wood Shrimp, Corys or Pleco be in any danger from the Prawn?

Thanks for your help and expertise!

 

[Veneer]

I recently purchased four "long-arms".

1) M. rosenbergii

2) Adult males may attain body lengths of around 16 inches, and total lengths (including chelipeds) of around 26 inches.

3) Plants may be consumed or uprooted.

4) Though an adult prawn would likely ignore your tetras, the rest would likely be consumed.

 

[YourPalCM]

Why would Petco even bother selling something like that which obviously has a very limited audience, and is, in all likelihood, going to be purchased by unsuspecting customers who don't know enough to ask on message boards first? Petco is stupid.

 

[Fruitbat]

YourPalCM....

I agree with you completely. I got one of the long-arm prawns (M. rosenbergii) in a mixed lot of 'ghost shrimp' that were intended as feeders. The prawn, tiny though it was, managed to survive. And it grew. And it grew some more. And then it grew some more....and more....and more (well....you get the idea). Soon it wasn't worried about being food for the fish....it was more concerned with fish for food! It took out a medium-sized Tiger Barb....then a small Schistura loach...and then it got taken out of the tank and dropped off at my favorite LFS. Last time I saw the beast it was approaching 10 inches long and had eaten everything in the tank they put it in.

They are pretty though. Here's what mine looked like:

 

[mattrox]

If they get too big they taste great! 8O

They also make great Barramundi bait!

 

[malcolm77]

Got one, took a few weeks till I really notice the fish population getting smaller. within 6 weeks ate everything in the tank, including a pleco. Was going to return it to the store, but I've kind of grown fond of it. Thought it would stop killing fish if I fed it frozen food. This thing seems to kill for fun! Only wish I could have something in with it that it won't kill. Tank looks kind of empty.

 

[bs6749]

Congratulations on the revival of a 4.5 year old thread.