Your truly are a lucky breeder! There is nothing more rewarding than to see a pair of fish raising and herding their own fry around the tank. There is also nothing more frustrating than to see spawn after spawn eaten by their parents! We have been breeding rams for years and have NEVER had a pair successfully raise their young. Out of the hundreds of spawns we've had, only one pair actually raised their eggs to the "wiggler" stage, then promptly ate them overnight. Usually, they will last 24 hours or so, then one of the parents will eat them! We have tried everything from group spawnings (multiple pairs in a single tank) to individual pairs in large planted tanks, and small planted tanks, but still no luck
You must have a pretty heavily planted tank for the fry to have been able to feed themselves for the first few days after free-swimming. The critical point is getting them past day 3 of free-swimming. After that, they are usually large enough to be able to eat newly hatched brine shrimp.
It's not uncommon at all to have the male chase/kill the female after spawning. That's why it's real important to have the in a planted tank, or have enough hiding places for the female to go after spawning. The male becomes extremely territorial, even with the female that he has just spawned with. If she doesn't have somewhere to hide, he will chase her incessantly, eventually cornering her and killing her.