would be interesting to know how they came up with the colour, this is not the sort of fish you would find in the wild.
I also think some of their advice is a little suspect. They recommend monthly water changes. Well, in my experience, you can't leave a containing Oscars for a month without a water change, not unless you have a very large tank with hardly any fish.
There advice on tank mates made me cringe a little bit as well. If you are going to recommend pacu as tank mates, please make it quite clear that these sort of fish can reach 24 inches quite easily in captivity. There aren't many people who have tanks big enough for pacu, let alone Oscars as well. Finding suitable tank mates isn't as difficult as was made out.
Also, you can easily clean your media with out upsetting the balance of your filtration system if done properly.