Should I Be Worried About My Guppies With My Gouramis?

[snowflight]

so my brother and me both have separate tanks, ooth 20 gal.

He has two gouramis that we think are female, two spotted cory catfish, and an algae eater.

he recently bought like 7 guppy fry that were about an inch long and the gouramis tried to eat them as of now he has 3, 2 died due to injury, 1 because of other things and the other we don't know.

then we temporarily put my other brother's new fish (2 koi swordtail females) in so we could cycle their tank. they attacked them too.

when the guppies get bigger should i be worried about putting them in with the gouramis?