What to do if Guppy is pregnant?

B

If you don't care about how many babies survive. Nothing. If you want them all to survive (that'll be a lot, like 20ish. Then those 20 will breed and you'll have so many more) then put her in a separate place. Like an extra tank or a clip/hang on net or container. Yes she will eat the babies if you don't her out quickly.

According to guppyaquarium.com, you can setup live plants like java moss or duckweed to provide hiding spots for the guppy fry if you don't have a separate breeding tank setup so the adult fishes can't find them.

Or you can use a breeding box?!

I think that's your best hope if you don't have a breeding tank.

if you have a small tank do nothing. a majority of the fry will be ate by the other fish and only 0-5ish will survive.

Buy a breeder tank in advance.