Yes, the female nidoran is blue and male nidoran is purple
It is impossible to catch a male or female nidoran in Pokemon Ruby. To get one you'd have to get it by trade.
Nidoran Female.
It's Nidoran
Pokemon Red/Blue Nidoran (male) learns 'Double Kick' at level 43 Nidoran (female) learns 'Double Kick' at level 43 Pokemon Yellow Nidoran (male) learns 'Double Kick' at level 12 Nidoran (female) learns 'Double Kick' at level 12 Pokemon Silver/Gold/Crystal Nidoran (male) learns 'Double Kick' at level 12 Nidoran (female) learns 'Double Kick' at level 12 Pokemon Ruby/Sapphire/Emerald Nidoran (male) learns 'Double Kick' at level 12 Nidoran (female) learns 'Double Kick' at level 12 Pokemon Diamond/Pearl/Platinum Nidoran (male) learns 'Double Kick' at level 9 Nidoran (female) learns 'Double Kick' at level 9
Both the female and male Nidoran can be found via Pokeradar on Route 201.
Nidoran is #29 (female) and #32 (male) in the national pokedex, and it is a Poison type Pokemon.
Both Nidoran male and female are found in the grassy area on Route 22.
Yes you can actually they are quite common.
Nidoran Male and Female can be found in these places: The route west of viridian city and the safari zone.
Both male and female are on Route 4
Nidoran (Female)- Route 35, Route 36 Safari Zone Nidoran (Male)- Route 35, Route 36 Safari Zone