What a beauty... I have one just like yours, roughly the same size. It's kept in a 36"x18"x16" grow out tank with Fluval 404 canister and eheim professional 2 canister. The water quality is pristine. Eventually it will go into my 60"x30"30" tank with 4ft sump and very powerful eheim pump and I will also use the eheim pro2 and Fluval 404. My previous 18" Dovii lived for 9 years in that 5ft tank. Just trying to get some time to reseal the big tank. All the best with your fish.
All my doviis large and small eat well. They love the Hikari medium cichlid sinking pellets and the large cichlid floating pellets. I buy them in bulk.