pregnant guppies

Question
QUESTION: Beginner breeder, tank size: 10gallon. I have a couple male mollies,three male guppies & 5 females. my question is that sometimes when observing the females... I'll suspect one being pregnant, the gravid spot will get darker, the belly will get bigger, & I'll place her in the floating breeder, (most of the time there will be babies) but the question is about the other times when the next day or so, the pregnant female doesn't look pregnant anymore, & there are no babies. Is there a reason for that?

ANSWER: perhaps she had them in the night and ate them??? Sometimes female guppies will gorge themselves with food too which causes them to look pregnant....what are you feeding your fish???? dave

---------- FOLLOW-UP ----------

QUESTION: Right, I can understand that. I feed them brine & crushed flakefood, They are feed once a day & what they can eat in three min.
if it is from her over eating why would she act as if she is pregnant, & about to give birth? hiding herself from the others, chasing them away...

Answer
Guppies are an odd fish... they can be as ferocious as a betta.  I once saw a small pack of them take down a four inch angelfish.  I had to move the angelfish to another tank to save its life from them.  She may be practicing... live bearers will often find a spot to have babies and then hang out there for up to a week before anything happens.  Their goal is to be obvious without being noticed... so if she stays in one place for a long while nobody in the tank will notice that she is having babies.  They are very vulnerable during the labor process... Its a brilliant philosophy... dave