Catalyzes the conversion of biologically active 11beta-hydroxyglucocorticoids (11beta-hydroxysteroid) such as cortisol, to inactive 11-ketoglucocorticoids (11-oxosteroid) such as cortisone, in the presence of NAD(+). Cortisol is the primary glucocorticoid in teleosts and is released to increase glucose bioavailability in order to meet the increased energy demands in response to stress. Functions as a dehydrogenase (oxidase), thereby decreasing the concentration of active glucocorticoids, regulating the hypothalamus-pituitary-interrenal (HPI) axis function in adult fish. Decreasing the excess glucocorticoids may be of relevance to brain function and neural proliferation. Plays a key role by catalyzing the oxidation of 11beta-hydroxytestosterone (11beta,17beta-dihydroxyandrost-4-ene-3-one) to 11-ketotestosterone (17beta-hydroxyandrost-4-ene-3,11-dione), the major fish androgen, that activates androgen receptor transcriptional activity. Catalyzes the conversion of 11beta-hydroxyandrostenedione (11beta-hydroxyandrost-4-ene-3,17-dione) to 11-ketoandrostenedione (androst-4-ene-3,11,17-trione), which can be further metabolized to 11-ketotestosterone. Exerts a dual role in fish by inactivating glucocorticoids and activating androgens