Large male S. officinalis above mature female in laboratory culture tank. The male is guarding this female from another large male out of view to the left. Male/male interactions can be very intense once mating and egg-laying begin. The bold zebra stripes on the fleshy 3rd arm of the males in this species is a way of telling the sex of an individual as females do not possess this component of patterning.
Maturity: Adult; Lab or Wild: Lab; Origin: E. atlantic, u.k. or france