Enables intracellular cGMP-activated cation channel activity. Predicted to be involved in cation transport. Predicted to act upstream of or within ion transport. Located in photoreceptor outer segment. Used to study achromatopsia 3. Human ortholog(s) of this gene implicated in achromatopsia 3 and color blindness. Orthologous to human CNGB3 (cyclic nucleotide gated channel subunit beta 3). [provided by Alliance of Genome Resources, Apr 2022]