Why are all my baby guppies female?

Answer 1

The male guppy would not (highly unlikely) kill the female on purpose. When this situation happens though, it's usually because of an imbalance in your aquarium between male and female fish population. The golden rule is 2 female for 1 male fish, otherwise it's likely that the male fish will "harass" the female fish, which will make her stress out and eventually die.

Answer 2

It may take a few weeks to be able to identify the males from females. I've never seen or heard of all fry being one sex or the other and I've raised thousands of fancy guppies. You will tend to get more females than males.

Answer 3

There is nothing to worry about. That is just the way guppies behave. In nature the female would avoid the male by moving away. In captivity it is always good to have a large enough tank with plants and rocks etc where the female can hide. Failing this, if you remove the male to another tank you will also stop the chasing and pestering.

Answer 4

They may appear to be female until they become fully grown... If they are all fully grown and still look like females, then you are very unlucky.