Re: Are goldfish colorblind, if not what colors can they see?

Dear Hank,

The goldfish is not color-blind. A number of studies have investigated the 
range of color discrimination of this animal (see references below) as 
well as putative underlying mechanisms. Generally, it seems that it can 
discriminate between a wide range of wavelengths, including ultraviolet. 
In that sense, it is tetrachromatic because its color vision is based on 
four types of cones (ultraviolet, short, medium and long wavelength-
sensitive). However, as shown by Neumeyer and Arnold (1989) the actual 
range of wavelength discrimination highly depend on the (white) luminance 
level of the room. When the luminance is diminuished,  discrimination 
between mid and long wavelengths (associated to a green-red 
discrimination) is abolished. In such conditions, the long wavelength 
sensitive cones have only a limited contribution to color perception in 
the goldfish. 

See also these related papers :


Yokoyama S. and Radlwimmer F.B.
The molecular genetics of red and green color vision in mammals.
Genetics 1999 Oct;153(2):919-32

Schaerer S. and Neumeyer C.
Motion detection in goldfish investigated with the optomotor response 
is "color blind".
Vision Research 1996 Dec;36(24):4025-34

Sjoerdsma T. et al.
Modulating wavelength discrimination in goldfish with ethambutol and 
stimulus intensity.
Vision Research 1996 Nov;36(21):3519-25

Coughlin D.J. and Hawryshyn C.W.
The contribution of ultraviolet and short-wavelength sensitive cone 
mechanisms to color vision in rainbow trout.
Brain, Behavior & Evolution 1994;43(4-5):219-32

Ohnishi K.
Development of color vision in goldfish: selective delayed maturation of 
blue vision.
Vision Research 1993 Aug;33(12):1665-72

Neumeyer C. et al.
Separate processing of "color" and "brightness" in goldfish.
Vision Research 1991;31(3):537-49

Spekreijse H. et al.
Induced color blindness in goldfish: a behavioral and electrophysiological 
study.
Vision Research 1991;31(3):551-62

Neumeyer C., Arnold K.
Tetrachromatic color vision in the goldfish becomes trichromatic under 
white adaptation light of moderate intensity.
Vision Research 1989;29(12):1719-27

Barry B., and Mathies R.
Resonance Raman microscopy of rod and cone photoreceptors.
Journal of Cell Biology 1982 Aug;94(2):479-82