Originally Posted by Brad M
Sounds like she is pregnant to me. Are you trying to breed them or is this just a happy little accident in your tank?
If you want them to live then more than likely you will have to make some changes with water quality tank mates filtration system and decor and food.
Tetras do not get "pregnant" or gravid because the females lay eggs, then they are fertilized by the male outside the female's body.
Originally Posted by Buu
These are both of the girl I believe have eggs. They are the best pics I can get! Still trying though. Would eggs be in that darken area? Or is it something bad (some disease).
This is a pic of a normal one for comparison. Totally see through and not rounded around the tummy. (Also I know my plants look horrible ATM. We just went through a long move where they had to go with lights for a couple weeks and my ozelot sword took a huge beating)
Male tetras are typically a bit smaller and more slender bodied than females. This is normal and does not necessarily indicate impending spawning behavior. If your tetras were to spawn (it is certainly not unheard of), you probably wouldn't even know it. They exhibit no parental care at all and are just as likely to eat eggs (and fry, if the eggs last long enough) as any other fish in the tank.
I had a group of von rios spawn in one of my tanks a couple years ago, right before I moved all the adults out. I had no idea until I found fry a few days after the parents were gone. They had apparently lived off the tank until I realized they were there, then they were pretty easy to raise on Fry Bites and crushed flake. Sponge filtration is a good idea for any fry IME. Power filters will suck them right up.