1. You should always research the different types of fish you are going to be housing together. Certain fish can be extremely aggressive and cannot be paired with other fish of different temperaments.
2. Only use medication in your aquarium when you are out of other options. You should use a separate tank to medicate sick fish as some medications can have harmful effects on healthy fish.
3. 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.