5 Aggressive Predator Saltwater Fish (Not for Everyone)

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Have you ever walked through a fish store and noticed a big massive tank with aggressive predator saltwater fish and thought “maybe I could do that”.
Well, yes you can.
Setting up a predator saltwater fish tank it’s not nearly as difficult as you may think. You just need to follow a few simple rules and make sure that the fish you’ve picked up are compatible with each other.
Having said that, before we go to the list of aggressive saltwater fish I’ve made for you let’s learn how many types of fish aggression are there.


Types of Aggression

Territory Aggression

This type of aggression usually happens when you introduce a new fish to the tank. The old inhabitants of your tank that have already established a territory may be aggressive towards newcomers. However, if you don’t have overly aggressive species the situation will probably settle down in a short time.

Predator/Prey Aggression

In this situation, there are two types of organisms in your aquarium. One of them is big enough to eat the other and often times these types of combinations don’t end in a desirable way. Make sure you’ve done your research before you purchase a new fish for your predator tank.

Food Aggression

Most of the fish in your aquarium are competing for the same source of food. If you have similar sized fish with similar characteristics then you shouldn’t have any problems. However, some types of fish are opportunistic feeders. In that case, a separate tank for them may be a good solution.

Spawning Aggression

Mating aggression can occur when two fish have paired up. This is one of the most beautiful sights you’ll ever see in your tank. It’s always nice to see their natural behavior. Usually, a pair of fish will show aggression by chasing other fish far away from their nesting area.

A list of Aggressive Saltwater Fish

Clown Triggerfish

The Clown Triggerfish ( Balistoides Conspicillum) also known as Baliste Clown is a saltwater fish easily recognized by many saltwater aquarium hobbyists.
This fish is one of the most popular saltwater fish and it’s easy to see why. The Clown Triggerfish has dramatic coloration and it’s very enjoyable to watch.
They are most commonly found in the Indian Ocean and the West Pacific Ocean. They grow up to 19 inches and should be kept in at least 120 gallons tanks.
Being territorial is what they are most known for. If you want to keep them with other fish make sure that you introduce them as the last fish.
They are aggressive eaters and will eat pretty much everything you give them. Be careful of introducing small fish or shrimp in your tank. They can easily become an expensive meal for your triggerfish.


Lionfish (Pterois Volitans) commonly referred to as the Common Lionfish, Red Lionfish or Turkeyfish is a venomous saltwater fish native to the Indo Pacific Ocean.
They are invasive species and can be found in the Caribbean Sea too. Lately, this situation is getting out of control. A lot of unaware hobbyists release them in waters with no real predator for the Lionfish where they can easily reproduce in large numbers.
However, the Lionfish is a great fish to have in a predator saltwater aquarium. They can reach sizes up to 18.5 inches and as big saltwater fish, you should keep them in at least 120 gallons tanks.
Avoid keeping them with smaller fish because they can easily become live food. Lionfish prefer live food but once acclimated they can learn to eat prepared foods.

Maroon Clownfish

The Maroon Clownfish, also known as Maroon Anemonefish is the most aggressive type of Clownfish. Like the other fish from their family, they have a symbiotic relationship with anemones.
Maroon Clownfish are usually found the in Indo Pacific from western Indonesia to Taiwan and the Great Barrier Reef. They are the biggest and most aggressive clownfish that grow up to a maximum of 6 inches.
They are very hardy fish and easy to care for. Recommend size of tank for them is at least 30 gallons. These species of fish are reef compatible and will make a nice addition to your reef tank.
They accept most of the commercial foods available in the aquarium hobby.

Snowflake Eel

The Snowflake Eel (Echidna Nebulosa) commonly referred to as the Snowflake Moray Eel, Clouded Moray, or Starry Moray is saltwater fish with snake-like appearance. 

They are found all across the Indo Pacific reefs mostly hiding in caves and crevices. In the wild, Snowflake Eel can reach sizes up to 39 inches. However, captive-bred specimens will not exceed 24 inches. 

Snowflake Eels prefer tanks with a lot of hiding places and room to swim. A minimum tank of 50 gallons is recommended. Most of the eels are very skilled escape artists. Make sure your aquarium is well sealed. 

They are truly an amazing specimen to keep. It’s very fun to watch them eating. They will accept most of the foods available in the hobby. 

Undulate Triggerfish

The Undulate Triggerfish (Balistapus Undulatus) is a saltwater fish with a very aggressive character. They are also known by the names of Orangelined Triggerfish or Orangetailed Triggerfish and easily recognized by their emerald green body with yellow-orange vertical stripes. 

These species are native to the tropical waters of the Indo Pacific Ocean. They grow up to 12 inches in length. It’s recommended to keep them in 180 gallons tanks. 

Undulate Triggers are very hardy fish. However, many hobbyists say that these guys are mean fish. Be careful when you are choosing tankmates for them. And never put slower fish in the tank. They will rip them apart in no time. As they get older they become the boss of the tank.

Undulate Triggerfish needs a diverse diet to thrive in home aquariums. Feed them squid, krill, clams, and small live fish if you enjoy watching live feeding. 

Final thoughts
I hope you liked the list of aggressive saltwater fish I’ve made for you. Some of the fish are a real piece of character. But really fun to watch, if you ask me.
However, having a big predator saltwater tank is not everyone’s cup of tea. Big fish equals a big tank. And maintaining a big fish tank is not a cheap thing.
Whether you are a fan of bigger aggressive saltwater fish or small saltwater fish, either way, let me know in the comments.

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