How can I tell if my female zebra danio is pregnant and not fat?
I danio will not get “pregnant” so to speak. Danios, zebra and otherwise, are egg layers. Normally you can tell if a female is about to lay eggs because the abdomen will be bigger on one side than the other. There are a few exceptions, but the most common live bearers are guppies, plattys, swordtails, and mollys. You can tell that these are pregnant by the presence of a black discoloration in the posterior part of the abdomen on the lighter colors and darker colors must be determined by body shape. Also, some plattys are “balloon” plattys and have a “pregnant” body shape naturally. These “look” pregnant when they have a more square abdominal shape.