I've got 3 female platys and 1 male platy. The make chased the females
incessantly until recently. Now one of the females looks very pregnant
and the male spends all his time sheperding her around. He even chases
off the other 2 females at feeding time. I even saw him chase the
betta.

I assume this is normal behaviour, but none of the stuff I've read
indicated that the father was that involved after impregnation.
Interesting.

--
Homo sapiens is a goal, not a description