Nope its not Just get a ratio of 2 females and 1 male...It takes about 4-7 weeks to have the babies, unless the females are pregnant when you buy them...My Molly has hers every 30 days
I have 2 females, and one male... they're almost always pregnant at the same time! I never had to adjust water conditions or give them special food to spawn... it just happens. Their worse than rabbits!