Care of Fish
Freshwater Aquariums
Aquarium Fish Species

How do you know a girl Oscar fish from a boy Oscar fish?

Answer

Wiki User
05/31/2009

There is no sexual dimorphism in Oscars (Astronotus ocellatus) although some amateurs may claim different. (Comparing fins has been touted but that's like comparing hair length in humans) The only two ways to tell are by actually netting and upending the fish to examine its' sexual organs (job for an expert) or watch them spawning and check out the shape of their 'tubes'. The female has a wide tube and is the one that lays the eggs. The male follows after the female and has a pointed tube it does not lay eggs.