HI,
I have kept south american cichlids for years, I ve found the Gold and green sevrons very easy to keep. I feed only Japanese Koi food it meets their protein requirements and enhances color and dosen't foul up your filtration. The species thrive on Vegatarian Diet, High protein or meat eaters tend to produce large amounts of waste that fouls tank filters rather quickly.
The white fish are gold sevrons, the orange are a hybrid rather expensive parrot fish a cross between sevrons and reddevils (a very grumpy meat eater).
Your filitration is the secret to keeping fish, You need as much as you can afford my large tanks have canister and reef systems that remove 100 % of the nitrates and urea from the water .
Another trick is to add small amounts of marine salt and I use a cup of crushed coral to 100 gal tank added to the gravel this buffers the water to 7.2 and you never have to worry about PH shock that can occur thru normal every day freshwater changes due to bacteria metabolism
WOrks for me hehe
My chiclids are over four years old now. they do get rather large and grumpy around 5-6 years old that mateing thing, I usally take them back and buy several new babies and raise the group together.
Doug