There's often a learning curve when it comes to successful spawning. Many fish like very early am to be in the mood. Do you have plants &/or sponge prefilters? those can help too.
IIRC, Neutral_Water, your tetra had different issues than shuhaib's. His/hers looks normal to me, just a female full of eggs. If they don't spawn to get rid of eggs, they may be "resorbed". I wouldn't advise treating with anything just yet...