Quinca mirificaMees, 1966 is a relatively large cardinalfish endemic to western Australia that displays a combination of unusual traits for an apogonid, including solitary behavior, conspicuous ephemeral sexual dichromatism, lack of a dispersing larval period, and production of non-functional oocytes. The ovaries are of cystovarian type and present a germinal ridge running longitudinally along the entire medial face. Ovaries show distinct division in oocyte composition, with a clear division between a rostral section composed of normal oocytes, and a caudal section that is composed of a mass of ∼13,000 non-vitellogenic oocytes of ∼0.2–0.3 mm in diameter, which after hydration, measure ∼0.8–1.0 mm. The egg clutch contains ∼200–250 eggs of ∼3.5 mm in diameter. Egg clutches sometimes break during the transfer, and males retrieve no more than ∼50% of the eggs. Courtship and mating include a “holding behavior” not observed in other apogonids, and the mating process (egg transfer) lasts up to about 90 seconds, the longest observed in any apogonid. Males (orally) incubate the eggs and hatched embryos for about 22–26 days, fasting during this period. Embryos hatch after ∼22 days (8.5 mm SL) and remain in the male's oral cavity for another four days feeding endogenously before being released as juveniles (SL = 9.5 mm). Females became sexually mature at about 10–11 months of age (∼77 mm SL). A study with two females (13 spawns) showed mean frequency of ∼33 days between mating events. Gross anatomy of gonads, embryology, and juvenile development are described.