I've got a question for you chocolate lovers; why is it called a chocolate cichlid if they are green and red?
Sent from my mind to my fingers to my phone to the MFK servers to you
My guess is because they also show a mottled brown pattern in addition to the green and red. Chocolates change colors constantly based on their mood so the green and red comes and goes. Also, H. coryphaenoides, the less common chocolate cichlid, pretty much keeps its chocolately brown color into adulthood.
Like most large SA cichlids, chocolates appreciate low nitrates and DOCs. Water changes are important. Like discus, keep the nitrates under 20 (preferably 10 or less) and you should be okay. They can be shy and pouty like oscars when you change things in their tank or when they're being picked on. They are not afraid to go after similarly shaped fish. Mine would harass one particular female severum to the point that I had to separate them.
I'm not sure how they'll do in your planted tank. They won't necessarily eat the plants (though they may) but will probably have fun ripping them all up and re-aquascaping. Mine would dig in sand. Most large SA cichlids are like this. Severums and Uaru will eat plants, but almost all the larger cichlids will dig them up and rearrange your substrate.
I kept my chocolate in pH 7.6 with a gH of about 7 and a kH of 5. So it's not super hard water but it does have a higher pH. The temperature ranged from 80 - 82F. I never had a problem. She mixed well with my other SA cichlids. Feed them a good quality pellet food (I used both Hikari Cichlid Gold and New Life Spectrum) and give them snacks occasionally (live redworms, frozen bloodworms or Mysis shrimp), but there's no need to feed them things like beefheart. (I don't feed beefheart to anything but discus and that's only because my discus are finicky about flakes and pellets. Even then, I rarely use it and instead go the frozen bloodworm/freeze-dried blackworm route.) You may also try a veggie pellet made with things like spirulina (I think Ocean Nutrition Formula 2 works) to round out their diet.
You will notice that they tend to sit nearly vertically sometimes, staring at the top of the tank. I'm not sure why they do this but I would guess they're waiting for a snack to fall into the tank. Maybe in the wild they wait for fruit/nuts/insects to drop down or something.
Here are a few pictures when it was in my 210 community:
