Hai
i keep Flowerhorns before ( about 9 month )
is very easy to keep. i had never facing anyproblem with the fish.
Flowerhorns r very strong fish , even i just remove all the water and immediately fill in tap water also no problems.
at that time i know nothing about aquarium, n-cycle ......................
i just do weekly water change and no fish died during 9 month after that i had give them to some people.
i change to keep marine tank.
so don't worry . u can keep it very easy.
but of'coz how to make the fish beauty or big head r anothers issue .