1. Clownfish do not always need to be with a sea anemone. Clownfish use anemoneís in the wild and they are not completely necessary in the home aquarium. If you insist on owning an anemone, you need to have plenty of experience to take care of it as they can be difficult to manage.
2. Purchasing fish that feed off of algae is a good plan to take care of an algae problem in your aquarium. You could also try cutting back the amount of lighting in the aquarium or get an algae treatment chemical to take care of any algae problems.
3. You should feed your fish a variety of food and not just flake foods. Mix it up with fresher foods from their regular diet. Giving them more a varied diet will increase the general health of your fish.