I had some left over Hikari Jumbo carnisticks from my arowana I fed to my 10" red devil.
After a few weeks, I noticed a significant change in the colour, his orange appeared more red and the white was body seemed brighter not to mention he ate up what ever I threw in within seconds.
Its pricey and sometimes a challenge to find. The sticks have a strong fishy like smell, they retain their form and if uneaten for a while they still float, no worries of it breaking up and messing up water.
My red devil loves it and produced great results I don't feed him anything else.
I recommend Hikari's carnisticks for any large fish.