Can live-bearer fish interbreed

YES...I HAD A PAIR OF REDSWordTAILS AND A PAIR OF GUPPIES. MY FEMALE SWordTAIL DIED...THEN MY MALE GUPPY DIED...LEAVING ONLY MY TWO FISH. IT WASN'T LONG UNTIL MY GUPPY HAD BABIES...AND THEY WERE RED, BUT I DIDN'T GET THEM SEPERATED IN TIME...THEY WERE EATEN. I DIDN'T TRY AFTER THAT TO BREED THEM. THEY SOON DIED AND I DIDN'T GET MORE FISH.