Immunofluorescence labeling identifies alterations in rod photoreceptor patterning and morphology. (A, B) Two views of rod labeling in wild-type 5 dpf larvae. (C) The rods in this mutant display an altered, “stringy” morphology. (D) In this mutant, the pattern and spacing of the rods is not normal. (E, F) In this mutant, the rods look normal in the outer nuclear layer, but ectopic rods are also visible in the inner retina, and sometimes the choroid fissure fails to close (F).