Originally Posted by Dallascowboys16
Thanks for the info. The female is starting to get somewhat round and just couldn't tell if she was pregnant.
Not to be a stickler
but your female red eye tetra is not pregnant. The only fish that can be pregnant are the livebearers (Guppies, Platies, Mollies, Swordtails, etc.) Once she is producing eggs, she will be considered "Gravid" not pregnant.
What is probably happening in your tank is that the smaller male is enticing her to get ready to breed by brushing up beside her. This is her que to start producing eggs which is why she is getting rounder. Once she is full of eggs, the courtship will become more serious and spawning will probably occur if the water conditions are right. That's the technical stuff
You should be aware that most tetras are egg scatterers and will spray their eggs along any thick planted area. However, it is not uncommon for them to eat their own eggs as will any other fish in the tank. Fish eggs are a natural food source to fish. If you are interested in saving the most amount of the eggs and fry, they are best bred in a separate tank.
Feel free to PM me if you have any questions on how to do this
Hope you don't mind the correction