Most of the flowerhorns are really aggressive. Mine attacks my hand, draws a bit of blood sometimes. So it is not a good choice if you are planning on putting in some other fish with it. As for the markings at the side, well they really are just black spots. But the Chinese hobbyists take them as chinese characters, something to do with good fortune and stuff I don't understand.
Flowerhorns are hybrids so they come in a wide variety of colors and stuff. Some also have unusually huge freaky lumps on their heads.
What elese do you want to know? They can get quite large so you would have to get a big tank. Not sure if 75gal will do. Maybe 90. :dive: