Not have them yet, but in the future I will keep some. I will suggest you to feed them a good source of protein enriched foods. Feed them a good mixture of high quality cichlid pellets, krill, frozen bloodworms, earthworms, crickets, etc. Feed them 2-3 times daily. But don't feed them Feeder Fish. Since they are messy eaters, they require a good source of filtration. Canister Filters are best for them. And lastly perform 30-35 % water change every week.
You have two nice looking Flowerhorns.