What happened to my neon tetra?

Question

last night i was watching my fish eat and i noticed that one of my neon tetras was really fat so i thought it is pregnant so i went to bed to get up and see in the morning and now she is not fat any more and im positive it is a girl can you tell me what happened to her

Answer 1

It's possible they spawned over night.  That would be the most sensible answer if she's been fat for a while.  Unfortunately the eggs probably got eaten by the other occupants of the tank.

Answer 2

She ate too much :)

Fish tend to get bigger after they eat too much. and then they poo, and they're back to normal again.. She must of hogged the food..  

Answer 3

I am in agreement, my Betta's will gorge themselves till they look like they will burst if I let them :)

I'm sure your neon was just greedy and ate more than her fair share.

Answer 4

Neons don't get pregant, they're egg scatterers.

If the fish wasn't big the day before, the fish probably just over-ate, neons are greedy little beggers.