Wow, wish I had seen this earlier, you got some really piss poor advice from some members here.
feed for 5 minutes - 3 times a day - feed beefheart, chicken liver, etc.
Are you people freaking high?
First off the OP's flowerhorn is only 5". Secondly he is feeding it a mix of pellets that are VERY high octane fuel, and are VERY large in size for this fish. (6mm) Both the 6mm NLS TherA and ChingMix pellets are very nutrient dense with high protein & fat in both feeds. You do NOT want to overfeed these types of foods to
any fish, and most certainly not a flowerhorn whose genetics are based on species classified as omnivores, not carnivores.
When feeding a juvenile fish, any juvenile fish, gauge the amount that you feed on the approx size of their stomach - don't just allow it to gorge itself for 5 minutes straight!
As an example, for a 5" FH 9 of the 6mm NLS pellets would more than fill its stomach, I would simply change it to feeding 4-5 pellets twice a day. Which is plenty for a fish this size!
The unfortunate reality is that the vast majority of people in this hobby, overfeed their fish. Add to that a diet that greatly exceeds a fishes immediate energy requirements, and the result is typically fatty deposition of the liver. The problem with fatty deposition of the liver is you can't see it with the naked eye, it can build up very quickly, and if not corrected can shave years off of the life of an otherwise healthy specimen.
And people wonder why their FH's don't live very long, well doh!
And just to show what kind of growth one can get by feeding NLS (exclusively), in a controlled manner (not 5 minute gorge-fests!), check out the growth on my KK over a 5 month period.
http://www.monsterfishkeepers.com/forums/showthread.php?370120-Update-on-my-KK
HTH