red pigment in zebrafish

David Lains david at
Wed Mar 30 01:47:00 EST 2005


Hi Chris

Zebrafish can not produce red pigments on their own.  It needs to come
from the environment.

We feed freeze dried Cyclop-eeze to increase this red pigment in the
males. It's ~35,000 ppt astaxanthin which is also the red "color added"
ingredient they feed to farmed salmon.  It is a naturally occurring
pigment produced by certain algae.  It's also great for increasing
fecundity as it is loaded with fats and fatty acids.

There are other red pigments added to food but Astaxanthin seems to be the
most common.  It is sold as nutrarose which is a spray dried algae that is
very high in Astaxanthin.

The ability of zebrafish to express the red varies from line to line. 
Most lines only the male express the red.  Some lines show little red in
the males and other show it in both sexes but this is a rarity rather than
the norm.

Best Fishes
David Lains <}}}><
Research Assistant
Zebrafish International Resource Center
5274 University of Oregon
Eugene, Or 97403

-----Original Message-----
From: owner-zbrafish at [mailto:owner-zbrafish at]
On Behalf Of clawrence at
Sent: Sunday, January 30, 2005 2:44 AM
To: zbrafish at
Subject: red pigment in zebrafish


Hi All,

Has anyone ever seen zebrafish with red pigment cells?  I've just noticed
that we have some fish with a noticeably orange-red tint to the anal fin,
different than anything I have ever seen in zebrafish.
Further, it is only present in males.

Anyone have any ideas?

Chris Lawrence



More information about the Zbrafish mailing list