Natural or Artificially Colored?

28th Jul 2019

Natural or Artificially Colored?

by: Bill Southern


Sometime back Ben made a post about a couple types of natural foods that were designed to enhance the coloring of shrimp, fish, etc. To make a long story shorter; I ordered some of the Naturose Natural Astaxanthin as well as the free sample of Algamac-ARA. These are refined natural products, not dyes, as I would not even think of trying to "dye" my shrimp....

I have tried the Naturose and my shrimp love it and I ended up mixing some in some home made food for my shrimp. This stuff does as it says and my red shrimp are redder, blue tiger shrimp bluer, CRS really solid white and red, and all the different species of shrimp I raise really colored up very nicely, but one thing very interesting happened as well.

My Yellow Shrimp turned BLUE GREEN:

Should look like this

This picture was taken about 2 weeks ago after feeding 2 or 3 days and I also stopped feeding these shrimp Naturose at that time as you can see they are quite blue green. They are now almost back to their normal color and within another week I should have yellow shrimp again.

Heck I even called the fellow I got the shrimp from about it... Can you imagine someone calling and asking if your yellow shrimp have ever turned blue? :lol:

This is what is interesting to me after actually seeing this first hand as we have all heard of dyed shrimp and this seems common with some blue varieties of shrimp especially. Well here is an accidental feeding experiment that produced a color change I consider as quite extreme in ALL my yellows not just one or two.

So I am thinking perhaps it is indeed food used by some sellers to turn their shrimp blue and this would also explain why after several weeks or months they fade as well as not producing blue offspring. Naturose mentions at their site and in instructions that the effect is not permanent as well.... Lucky for me.

If it can be done with natural foods then coming up with a artificial food type dye would not be all that difficult. I know this is the agreed suspect method used to dye shrimp (food) but here I came across accidental proof (for me anyway).

There are only a couple shrimp that are actually breeding blue like the Blue Pearl Shrimp and Blue Tiger Shrimp and actually have blue young. Then you have the host of "Blue" varieties that show up at auction sites that buyers report to be "Dyed". I am curious as to how blue they actually would have gotten, but not curious enough to try it again as I like them yellow.

Just thought to share as it seemed pretty interesting to me...




After a couple weeks or so my Yellows are almost back to normal:

Interesting accidental experiment.....

I am not sure the molting actually was the key to changing color back to yellow as some changed back without molting. At first I thought it had something to do with it, but now think it a coincidence. Some females even had green eggs as well as some having green saddles. The berried females seemed to stay blue green until delivering young then molting then slowly turning yellow again. A couple are still not fully back to normal but for the most part are all yellow again, but the ones saddled at the time of the change to blue green now are carrying light green eggs. All the young born of the others are showing the normal yellowish tint you would expect.

Both sexes changed color, but the females were indeed affected more and took longer to regain their Yellow color and some (2) females are still quite blue although obviously changing.

This was a very interesting learning experience about the ability of food to influence color. As far as if the coloration was in the body tissue or exoskeleton I would not have a definite answer. My theory at this point would be that the astaxanthin was able to physically change the natural color as long as the shrimp ingested it replacing Yellow with Blue Green. As to how or where the actual chemical change happened I have no clue.

There was a young man from China saying he is able to catch a blue species of shrimp from a natural spring in his country but after living in captivity they lose the blue color. So this makes me wonder if in his case it it minerals in the water? Or perhaps something in their diet in the spring environment that they eat causing the blue coloration. The two cases seem similar although unrelated. I am guessing (only a guess) that this is too food related, perhaps the algae they are eating? After all a specific type of algae is also the source of Astaxanthin used in Naturose.

Perhaps the blue shrimp you see for sale are indeed naturally tinted by diet and lose color due to a missing nutrient and were not purposely dyed....

This is very interesting and I almost wish I had the time and resources to experiment more by trying to re-introduce the blue into some of these shrimp that fade weeks or months after purchase. If anyone out there has purchased such shrimp that have lost their blue I'd be glad to send a small portion of Naturose and see what happens...