Juveniles frequent shallower areas, while adults occupy deeper areas. There are other, subtler differences, but they aren't reliable given the general variability within species of the family Cottidadae. My first specimens of reticulates came up in a dip net from the North Fork of the Yamhill River near Carlton, Oregon. I would find out at spawning time that one was a male and one was a female. Young reticulates like these exhibit a rough checkerboard pattern on their sides which is faded on adults.
Adults do have a more attractive dorsal-fin pattern, a myriad of wavy lines.
The orange outer edge found on dorsal fins of many sculpin species is not especially pronounced in this one. Spawning males become very dark on their face and anterior dorsal body areas. Females at spawning time appear unchanged in color or body pattern. The other reticulates I collected were rotund, ripe females in mid-February. They were found in areas of submerged logs in somewhat shallow water.