When Molly fish are pregnant, they develop large, swollen abdomens with large dark spots near the pectoral fin. Mollies start to develop this appearance up to a week before giving birth. More »

www.reference.com Pets & Animals Marine Life Fish

When a female gourami fish is pregnant, her belly is swollen at all times, according to Fish Spawn. The male builds a bubble nest before the bulge is visible. A bubble nest looks like a cluster of many tiny bubbles that ... More »

To tell if a black molly fish is pregnant, look for swelling and a black pregnancy mark on its lower belly. Black molly fish are almost always pregnant, meaning the pregnancy mark is almost always there. More »

To tell if a black molly fish is pregnant, look for swelling and a black pregnancy mark on its lower belly. Black molly fish are almost always pregnant, meaning the pregnancy mark is almost always there. More »

Primarily white with black spots, reminiscent of the Dalmatian dog which gives the fish its name, Dalmatian Mollies are hybrids of the Sailfin Molly (Poecilia latipinna). They are peaceful, freshwater fish, that originat... More »

www.reference.com Pets & Animals Marine Life Fish

Discus disease and stressful conditions may cause fish to develop black spots on the body. It is necessary to test the pH levels, temperature and oxygen levels in the aquarium to determine the cause of the condition. More »

Male fish may have larger pectoral fins and small white spots on their heads and pectoral fins. Female fish may be larger and rounder than males. More »