胎生鱼。 区分雌鱼和雄鱼。 注意宠物鱼交配的迹象。 检查雌鱼是否有因为怀孕而产生的腹部隆起。 查看鱼是否产生了红色或者黑色斑点。 决定如何处理幼鱼。

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Guppies, mollies, swordtails, and platies are probably the most common live-bearing aquarium species. The males and females of these species mate, after which the females form eggs within their bodies. Over the course of a month or two (for most aquarium species), the eggs hatch into fish, and the mother gives birth. Search for the name of your species online to discover whether it is egg-bearing (oviparous) or live-bearing (viviparous). As a general rule, male fish of live-bearing species are brighter or more elaborately colored, and have a narrow, long anal fin on their lower side next to the tail. Females tend to be more drab, with a triangular or fan-shaped anal fin. If you can identify their sex, you'll have an easier time telling whether two fish are fighting (typically two males or two females), or whether they are mating or preparing to mate (one male and one female). Some species are more difficult to tell apart, and may require an expert from an aquarium store. Different fish species can behave very differently during pair-bonding, amplexus, and other mating-related behaviors. In many species, including most gouramis, the male chases the females around energetically, sometimes even causing scrapes, bites, or other damage. In others, such as discus, a male and a female will work together to defend one area of the tank from other fish. In either case, when actual mating occurs, this may involve the male and female gripping each other, turning upside down, wriggling around each other, or more subtle activities that are difficult to see. The female fish will grow a bulge at the back of the abdomen. The abdomen typically grows over the course of 20–40 days, either into a large, rounded shape or a "boxy" shape.  Some species such as balloon mollies have a natural bulge further forward, just below the gills. Overweight males may develop a bulge in the front chest. If you skip feedings for two or three days, an overweight bulge may shrink, while a female's pregnancy bulge will not. Pregnant female fish...