Guppies wouldnt be my choice! The males are the colourful ones and so might be prefered.
If you have one male / two female then you’ll soon have 100 guppies.
If you have two male / one female then you’ll soon have 100 guppies and a very stressed female.
If you have three males then they will all fight.
Small Tetras of some description would be better. Single species, at least six.
Please cycle the tank properly before adding fish, which will take around a month. If you don’t know what this means then please don’t do anything else before reading up on this