Clowns are omnivores, so you want some vegetable matter in their diet. Many commercial brands are designed for omnivores. The majority of the diet should consist of meaty foods, but having some plant matter is important as well. I like a mix of foods designed for carnivores and omnivores staggered through out the week. If you make your own food ie blender mush, you can add some spirulina and/or dried seaweed sheets, peas, broccoli, etc. for the desired effect. SW
plants are best and should always be included. HTH
BTW firefish are peaceful and kind of shy. I would make that my first fish addition so it can get acclimated and claim some territory before the more aggressive fish are introduced. Peaceful fish go in first and the tank should be stocked slowly over a few months for best results.