I have another question. Being new to owning flowerhorns I don't understand why he is losing his color. This is his 4th day in my tank and he has almost no red on him anymore. He is eating well and swimming around. He usually stays closer to the bottom of the tank but I think that is because he is not used to the water pressure yet (he was kept in a 5g tank before I bought him). Does he sound like he is sick?
It takes a while for the fish to settle in. What size tank are you using and have you checked your water parameters? I'm not saying your water it's bad but if it's different than what they had at the pet store this could be a possibility why it's losing color. It can take a fish while over a week to adjust to a new environment parameters and temperature. What is your current temperature on the tank?