I've had a problem with my Danio too. I determined that she just ate too much and was bloated. I recommend decreasing food and seeing what happens before jumping to conclusions of a deadly disease. But I do recommend separating your Danio just in case and decreasing food.
Thanks everyone for the replies... It was just the excess food... As they usually all the food even which is for others. I started giving the the food once in a day for a week and made sure other are also able to eat by blocking these two and now they are fine.
I have raised zebras and , mostly, giant danios ; that is too large for eggs . My guess would be disease "dropsy". What I would do is wait for them to die and make sure no other fish also have the problem. Dropsy does not seem to be very contagious.