How Many Fish in a 120 Gallon Saltwater Tank?
Saltwater stocking is more conservative than freshwater — marine fish need more room, produce more waste, and many are territorial. The calculator below is pre-set to 120 gallons (saltwater); add your livestock and it'll flag reef-safe, aggression, and tank-size problems.
Example 120-gallon saltwater stocking ideas
- Large mixed reef: yellow tang + a dwarf angel + clownfish pair + an anthias harem + a wrasse + full cleanup crew.
- Big community: tang + foxface + clownfish + chromis school + gobies.
- Tang-capable system: a 125 gal+ tank can responsibly house a blue hippo tang with strong filtration.
Cycle the tank fully, add the most peaceful fish first and the most aggressive last, and quarantine new arrivals. Run your exact list through the calculator above.
Reef fish for a 120-gallon saltwater tank
Photos via Wikimedia Commons under their respective licenses — click a credit for the source.