Yup, you could. I realize that a lot of people are going to say that you can't... You can. As long as its cycled and you are doing enough water changes they will be ok. I keep guppies with my betta in a five gallon. Don't add to many guppies though!
Theoretically you could; based only on bioload and space and such. But in actuality, you can't. Guppies need a minimum of 10 gallons as they are very active fish. You could get some shrimp or snails, though.
acoording to MY experience, you can. my tank is a 6 gallon, and Pluto the metallic halfmoon lives with Jewel and Fluffy, a pair. At least they used to, because Jewel is expecting very soon. Pluto tries to eat the fry. that is why they are kept seperately in a 5 gallon.
oh and also, it depends on the personality of the betta. most books i've read say something like don't mix guppies with bettas the bettas will mistake the guppies for rivals. especially male guppies. Hope this helps! ;)
Thank you monica12980.The betta is a baby betta so I don't think he will be to agressive but I would defenitly still watch.I've had bettas and male guppies before and they never fought but it does depend on the fish.