Recently I wrote a blog post called Redder Red Cherry Shrimp . The post focused on what affects the coloring of Red Cherry Shrimp. There was a comment left on that post that included some information that I forgot to mention:
If you want a redder color, I have heard that it can depend on what they eat, to some extent. Wild caught salmon have the red colored meat because they eat crustaceans so a fun experiment might be to try feeding a crustacean based food.
The chemical that cases the wild salmon to have so much more color in them is Astaxanthin. Astaxanthin is naturally found in algae and crustaceans (among a few other things).
When a Dwarf Shrimp consumes a food that contains Astaxanthin (found in small amounts in shrimp based foods and in larger amounts in foods intended to deliver a large dose of Astaxanthin) color changes do happen. Red Cherry Shrimp that are not geneticly predisposed to display deep, dark reds will display a bit more color. Some shrimp, such as the yellow shrimp, may even display a totally different color, such as a blue green.
Once this food source is removed and the shrimp no longer eat Astaxanthin the changes will be reversed and the shrimp will revert back to its natural coloring.
I personally have done a few experiments with food heavy in this chemical. I used it with Red Cherry Shrimp, Yellow Shrimp and Crystal Red Shrimp. The results were quite variable, but the overall theme was a slight color change. The Red Cherry Shrimp seemed to get a bit darker, the yellow shrimp seemed to turn blue green, and they Crystal Red Shrimp seemed to have a bit more contrast.
There was no downside to the food that contained this chemical, and in fact it is known to be a great antioxidant. If you want to find a food high in Astaxanthin look for foods that their first ingredient is Krill or foods that advertise Astaxanthin as an ingredient.
