Are puffer fish reef safe?

Saltwater reef aquariums are popular for the wide variety of beautiful fish, coral, and other interesting sea creatures that they can support. They are also notoriously difficult to maintain. One of the biggest challenges of a saltwater aquarium is finding a safe balance of reef life. 

Many popular reef fish, like puffer fish, can be aggressive toward other species and make it difficult to maintain a diverse tank ecosystem. But puffer fish can be reef safe if you select the right combination of species and varieties of animals for the tank.

What does “reef safe” mean?

In the context of saltwater aquariums, reef safety refers to the viability and survival of smaller fish, invertebrates, and coral. In an unsafe reef aquarium, these creatures would be constantly injured or eaten by larger predators.

Since fish have complex personalities and interactions, it’s not always possible to keep a reef 100% safe. Many fish that are categorized as “reef safe” can still be aggressive toward certain tank companions, and their individual behaviors can vary. But choosing the right sizes and species of animals can minimize damage and loss of life.

Predators in reef aquariums

Most fish that are considered unsafe among smaller companions in a reef aquarium are predatory in nature. Carnivorous predators have a natural instinct to hunt and eat smaller fish and crustaceans when they have an opportunity. Also, some fish will go after the tiny animals within living corals, damaging the reef over time.

Aggressive predators like triggerfish are examples of the kinds of fish that are listed as unsafe for a reef aquarium. Pairing these kinds of fish with smaller animals will most often put the prey in danger. Keeping larger predators is possible, but normally only if they are isolated.

Some predators though – like puffer fish – if carefully selected, can still be combined with smaller creatures in reef tanks.

Puffer fish types and behavior

Puffer fish, or pufferfish, is a name that refers to dozens of closely related species and varieties of fish. 

The name comes from their ability to “puff” their bodies to appear larger and deter predators by filling their stomachs with a large volume of water. A closely related fish, the porcupine fish, has this same defense mechanism and is often referred to as a puffer fish as well.

Pufferfish are toxic saltwater fish, in the wild, puffer fish harvest a toxin from bacteria in their diet to make their bodies poisonous to predators, but they are not toxic when born and raised in captivity.

Puffer fish can vary greatly in size depending on the variety and environment. Dwarf puffer fish species are only an inch long while others can grow up to two or three feet. 

Virtually all puffer fish are territorial. They are also aggressive hunters. Some are known to lie in wait to ambush their prey from small hiding spots. Some are also known to eat reef coral.

Most Common Types of Puffer Fish That You Should Avoid

There are at least 120 species of puffer fish around the world. Some are more common than others, but most of them will not be able to safely live in a reef aquarium, except maybe the smaller species (Toby puffer). Here are four of the most common types of puffer fish that people wonder are reef safe.

Valentini Puffer

The Valentini puffer fish is a toxic puffer fish and should be kept in fish-only aquariums. The Valentini puffer is not considered to be reef safe due to the toxic nature and that they like to eat coral, shrimp, and snails. These fish are mostly peaceful and should get along with just about any other fish you decide to pair it with.

Blue Spot Puffer

The Blue Spot puffer fish is another fish that should be kept in fish-only aquariums. They have the ability to poison areas of the tank, and they will nibble and eat your coral. It is recommended that these puffer fish should have one single environment in their tanks, not including coral.

Dogface Puffer

Dogface puffer fish are named as such due to how they interact with people. These fish are super fun and outgoing, making them a great choice for an aggressive type of aquarium. The dogface puffer fish is not considered to be a reef-safe fish.

Porcupine Puffer

The Porcupine puffer, cute as it may sound, produces toxins and nips on coral. They also eat tiny inverts, so this puffer fish is also not considered to be a reef safe addition to your aquarium. It is best to keep them in fish-only environments as they can be kept with different types of fish.

Tips for keeping a reef safe with puffer fish

In spite of their aggressive nature, puffer fish are popular among aquarium enthusiasts. They are very intelligent and have interesting personalities.

Although they work best in fish-only tanks with equal-sized companions, it is possible to have a safe reef aquarium that features puffer fish. Here are some things to consider before introducing puffer fish to your tank.

Size matters

If a puffer fish is the biggest kid on the block, it’s more likely to revert to its instincts and bully smaller fish and invertebrates. Choosing smaller species of puffer fish for a reef tank can help mitigate the danger to other tank denizens. 

“Tobies”, “Valentinies”, and “Saddles” (sometimes used interchangeably) are some examples of popular, small varieties of reef tank puffer fish. Each grows to only about three to four inches long. Although these smaller puffers are often described as reef safe, it still requires some thought and care to keep other reef dwellers out of danger.

Regardless of their diminutive size, small puffer fish are still predators at heart and will go after small shrimp and crustaceans, so it’s also important to be careful about which other animals you choose to keep in the reef. Having large shrimp or crustaceans that are more equipped to defend themselves can deter some of the smaller puffer fish species from going on the attack.

In most cases, a tank between 50 and 75 gallons will suffice for the smaller species. A tank closer to 125 gallons will be better if you are planning on putting other fish in, too.

You will want to make sure any sand or gravel you are putting into the habitat is clean. You can add rocks to provide your fish with plenty of places to hide.

Avoid certain invertebrates

Puffer fish love to scour and hunt the reef in search of tasty invertebrate snacks that make easy prey. Crustaceans, sea snails, and even clams are common in their natural diet and make easy, tantalizing treats within a closed environment like an aquarium. Puffer fish especially love shrimp and will wipe out many small ones easily.

If you are not intentionally feeding invertebrates to your puffer fish as part of their diet, it may be safest not to introduce them into the tank at all. Either look for crustaceans and other invertebrates that puffer fish will avoid eating, either due to their size or natural defenses, or consider avoiding invertebrates altogether.

Keep a feeding schedule

It’s common to visit large public aquarium exhibits and see multiple aggressive predatory fish like sharks and barracudas happily comingling with smaller fish that they would normally gobble up in a heartbeat. Aquarium managers accomplish this by keeping the apex predators in the tank well fed at all times on a regular schedule.

When fish know food is on the way, they often quickly learn that they don’t need to expend energy working at it. When adding puffer fish to reef aquarium with smaller prey, keep them isolated from the others until they become accustomed to an adequate and regular feeding schedule. Stick to the schedule after mixing them in with the other animals, and they may just behave themselves.

Keeping small prey animals, especially invertebrates, safe in a reef aquarium with puffer fish is never a guarantee. Animals have instincts that are not always easy to overcome. But if you take into account their tendencies and eating habits, it’s certainly possible (perhaps with a little trial and error) to maintain a safe, healthy reef.


If you absolutely have to have a puffer fish, it is best to create an environment for them that they will thrive in. This means you should have a tank for them that is separate from a tank with a reef in it. The best way to determine exactly what a puffer fish needs is to do some research on the specific species that you are going to purchase.