Tuesday, September 14, 2010

Freshwater Prawn Drawdown

Almost too beautiful to eat.

A look under the kilt.

Dorsal view.

If you are not the lead shrimp, the view never changes.
Of course, if you are a shrimp, it's good to not be on point.

The RAS (test: remember what that stood for?) needed a flushing last week so I popped the knife valve open and drained most of the water out.
This allowed me to get a good look at my livestock and they seem to be growing and thriving.
In a drawdown, I drain the water through a bottom drain and with it goes bottom sediments that build up over time. Once the tank is cleaned, I refill with fresh well water.
The well water comes in at 74 degrees, but the very tropical prawns seem to handle that temperature change (the old tank water would have been warmer due to absorbing the summer heat).
My system rarely needs a drawdown and is very water efficient. On a daily basis, I exchange about 5 gallons of water at the most.
I open the valve for just a moment daily to flush a pulse of uneaten food, etc out of the tank and into the happy plants that grow near the RAS.
A few days after taking these photos, I almost lost the lot of them when a pipe connection came loose.
Most of the aeration in this tank comes from the sprinkling water that returns from the filter barrel. A pump in the tank sends water to the barrel, where it flows through filter media. It returns to the tank (R = recirculating) by spraying back into the tank, thus aerating the water.
I just happened to walk out to feed them a late night snack and discovered the malfunction.
The shrimp were all at the surface (very rare) because that water was the most oxygenated.
The poor things almost suffocated.
I did some late night plumbing repairs (and improvements) and all was well.
Scary business though.

Prawnzilla loves to hide under the substrate fencing and would not come out for a better photo.
He is totally awesome and dominates the tank.
Here's a quiet, not very exciting, yet kind of soothing, video of the prawn parade.

No I haven't eaten any yet, but I think their population will have a sudden drop soon.
I'm thinking broiled like lobster.


threecollie said...

I just can't believe how big they have grown! Glad you caught the malfunction before it was too late. They are really cool.

Vicki said...

Have you named them yet? Nice looking shrimp farm, excuse me, RAS you have there!

Sayre said...

Some of those are HUGE! Do you eat the big ones first or is there a size limit (like fish)?

Dani said...

So...are yah gonna invite us all over when it's time to eat?

Thunder Dave said...

You know I've been thinking about this for awhile, so I would either go broiled or grilled in the shell; with a little garlic butter salt and pepper. Yum, yum!

kathy a. said...

looks like you have quite a few prawn-zillas.

SophieMae said...

DUDE! How cool are they?! That first pic looks a bit like a whiskered dolphinish creature. Never noticed that before.

who wouda thunk it?? said...

didn't yer mama tell you not to play with yer food! haha

edifice rex said...

oooohh, shrimp! nomnomnomnom!

Deb said...

Yum...that's all this crustacean-starved Minnesotan can say...

LauraHinNJ said...

Won't your students enjoy a shrimp boil?

; )

Kimberlee said...

I hope you can get a photo of that big'un sometime. If his legs are any indication, he's a monster!

cinbad122 said...

Your children have grown so much since I saw them last! :)

Floridacracker said...

Thanks y'all!
I am setting up the school system again and almost ready to order a new batch to raise.
This time we are ordering them earlier in the year so we grow them out within the school year.

lisa said...

I'm with Dani, are we invited for dinner?

Matt said...

Do you sell small ones that i could raise in my aquaponics system? i'm in FL. and could pick up.

Steve BlackHawk said...

I am also interested in purchasing babies if available.or in getting info on where to buy these guys.....any help would be greatly appreciated