A goldfish is pregnant when the abdominal cavity is swollen, after which the female goldfish lays the eggs and the male goldfish fertilizes the egg sack. Identify signs of a pregnant goldfish with helpful information from a practicing veterinarian in this free video on pet care.
Let's talk about how to tell if a goldfish is pregnant. Now goldfish are egg layers, and so they develop eggs within their abdomen, and when they are pregnant or gravid with eggs, that abdomen is going to expand. So, you're going to have a normal idea of what your goldfish looks like, and when that belly expands, there is a possibility that she is pregnant. Now there are other things that can cause an abdominal cavity to swell, like infections and cancers and things like that. And so if your fish is, you know, showing signs of problems, let somebody know. But pregnancy in these guys is pretty easy to tell because they have that swollen abdomen. They lay those eggs, and then the male will come by, if there is a male, and fertilize them outside of the females body. And then the fry can develop. But just look for a swollen abdomen, and that's a sure bet, typically, that a goldfish is pregnant. Now, not all fish are egg bearers. Some are live bearers, but goldfish, what they do is they are going to swell up their abdomen, and lay those eggs attached to something. And so the male goldfish, very commonly, sometimes, will have a little white edge of their gill slit that appears when they are ready, also, to fertilize, so the female knows. And so that male will approach the egg sack and fertilize it. And, at that point, after fertilization can occur, those little baby goldfish can start growing and then hatch out of their eggs, and live a full life.