Differences in Male & Female Opaline Gourami

The opaline gourami, also called the marbled gourami, is native to the Mekong basin and Yunnan in Southeast Asia. Its native habitat includes marshes, swamps, wetlands and canals. It is a hardy aquarium fish with a silver blue body and dark blue markings on the side. It breathes directly from the air, taking sips at the top of the aquarium. There are several observable differences between the male and female.
  1. Dorsal Fin

    • The dorsal fin is a fin located on the back of the fish. Its main purpose is to stabilize the fish as it swims. Differences in the dorsal fin are the best way to distinguish the male and female opaline gourami. The male's dorsal fin is quite long and pointed, while the female's is shorter and more round. Though some females have long dorsal fins, they are still distinguishable by the rounded tip.

    Anal Fin

    • The anal fin is located on the underside of the fish near the tail. Like the dorsal fin, the purpose of this fin is to help stabilize the fish. On the male, the fin is long and pointed. The female's anal fin is shorter with a more rounded tip.

    Size and Nature

    • The adult fish grow up to 5 inches in length. When comparing a male and female of identical age, the female is slightly larger than the male.

      The male fish is territorial. In a small tank environment, multiple females accept each other peacefully; however, multiple males will fight. The male is also more aggressive during mating. When mating these fish, provide plenty of plants, rocks and other aquarium decorations so the female can hide when the male becomes overly aggressive.

    Mating Ritual

    • When the fish are ready to breed, the male designs and builds the nest. He blows bubbles and arranges them in a nest at the surface of the aquarium or among aquarium plants. When it is complete, he swims back and forth between the nest and female with his fins flared and tail raised to entice her. The male is also the one that tends the eggs and takes care of the young.