Corals

Tankmates: Reef livestock by definition, but corals sting or chemically attack each other - plan spacing. Avoid coral-nipping fish (most large angelfish, many butterflyfish, some triggers and filefish). Larger crabs and some urchins can knock over or graze corals.

Feeding: Most corals sold for reef tanks host zooxanthellae and get most of their energy from light; supplemental feeding helps growth and colour. Non-photosynthetic corals (some gorgonians, sun corals, Dendronephthya) are exceptions that need frequent feeding.