good to hear your water was OK, and going by the pics, the fish weren't in great shape when you got them. the first pic has a split tail (keep an eye on it for infection) and the second looks starved, it wouldn't surprise me if the second one was a year older than the first. I'd also guess they are wild caught.
I wouldn't feed so much though, twice a day is plenty, a fish can easily grow 6 inches in a year on being fed 2 times a day. and too much after a period of too little can cause problems too. that's why they give starvation victims (people, dogs, cats, etc...) only very small amounts at first.
salmon is great for your fish, but will really dirty up the tank. omega one cichlid pellets has whole salmon meal as it's first ingredient, and all my fish love it. I'd go with that instead of fresh fillets.