Fish Compatibility in Your Saltwater Tank

By: Michael Phife


Like all living creatures, there are some fish that get along peacefully with others, and there are some that will attack everything in sight. In saltwater, there are so many fish that it is hard to keep track of which ones are peaceful, which ones may attack smaller fish or invertebrates, and which ones are aggressive towards pretty much everything. In this article, I will be listing which types of fish are generally found in most aquatic stores, and their overall temperament with other fish mates.


Peaceful or Aggressive?

As mentioned above, picking out the fish that you want to live in your aquarium is one of the biggest decisions you will have to make for saltwater. There are so many options to choose from, but most options are limited if you decide to do coral and specific invertebrates. Sometimes you may think that a fish will do well with other tank mates or corals, but one day they will just flip out and start attacking and eating everything in sight (Triggerfish are very notorious for this). You should always research each species of fish you plan to purchase, because some have slightly different temperaments than the majority in their direct family line. Despite this, I will at least give you a generic synopsis of how each family of fish behaves towards tank mates. It is also worth noting that it would be almost impossible for me to list every single family of fish and what they are compatible with, but I will try to list some of the more common aquatic marine fish you can purchase, and their compatibility with other fish and coral.

  • Damsels – Reef safe. Highly aggressive towards most fish the same size as them.
  • Wrasses – Both reef safe and not reef safe depending on species. Some may become territorial and attack other fish.
  • Gobies – Reef safe. Compatible with most fish.
  • Blennies – Reef safe. Compatible with most fish.
  • Angelfish – Not reef safe. Might attack smaller fish and invertebrates.
  • Butterflyfish – Caution with reef. Compatible with most fish.
  • Surgeonfish – Reef safe. Compatible with most fish but can get aggressive towards other tangs or if tank is overcrowded.
  • Basslets – Reef safe. Compatible with most fish.
  • Anthias – Reef safe. Only aggressive towards other aggressive fish.
  • Hawkfish – Caution with reef, may nip at softer corals. Will attack bottom dwelling fish.
  • Lionfish – Not reef safe. Typically peaceful but may attack small fish and invertebrates.
  • Rabbitfish – Caution with reef, may nip at softer corals. Peaceful with most fish.
  • Triggers – Not reef safe. Sometimes will attack other fish regardless of size.
  • Cardinals – Reef safe. Compatible with most fish.
  • Jawfish – Reef safe. Compatible with most fish.
  • Puffers & Boxfish – Not reef safe. Typically peaceful but will attack invertebrates.
  • Seahorses – Reef safe. Compatible with prawn fish and peaceful fish.


The Coral Reef and Its Inhabitants

There are countless fish that dwell on the reef and even areas along the perimeters of reef beds. Nearly one-third of all known marine fish live on coral reef beds, which is shocking if you research how fast the reefs are diminishing in nature. The Florida Keys, which is one of the most popular reef beds in the United States, has lost roughly 90% of its coral reef from the year 1975 until now. On top of that, the worldwide loss of coral reefs have been an approximate 20% since the last recorded observation. This is a catastrophic number considering the reef beds have been around for over 450 million years, and within the past few decades alone they have been plummeting in their survival. This is also affecting the fish that inhibit these regions, and is also causing them to die off. This is crucial to know as aquarium hobbyists. We can take part in our conservation efforts to help educate others and restore what is becoming lost, despite looking at small fractions of it in our own aquariums.

Time Lapse of Florida Keys Diminishing