Even though he’s a beauty, this guy has the reputation of being the most aggressive triggerfish! Which means the Undulate Triggerfish or Orange-lined Triggerfish may be the most aggressive fish, period! Actually they are okay when they are small, but get cantankerous as they get older.

Make sure you have a large aquarium or not very many other fish. Give it lots of room and a cave or rocks to retreat into.

The Undulate Triggerfish or Orange-lined Triggerfish can be worth keeping since it is lively, colorful, and will grow to be a nice pet, taking food from the owners’ hand! Watch your fingers though, the teeth are very sharp and can deliver a painful bite.

For more Information on keeping this fish see:
Guide to a Happy, Healthy Marine Aquarium

Undulate Triggerfish adult, Balistapus undulatus

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Very beautiful, very mean

The Undulated Triggerfish is as beautifully striped as it is mean. As juveniles, they are not as aggressive but they become 12″ murderous monsters as adults! If you want to keep them alone in a 180 gallon tank as the only fish, then by all means buy one! Just be careful when you put your hand in the tank, as these nasty buggers can leave quite a nasty bite mark on your hand, arm, or whatever else it can grab. Still not wary? Then this is the fish for you! They make grunting sounds, spit water, chew electrical cords, are generally obnoxious and will steal your credit cards! Undulate Triggerfish have been known to chomp through clams, which is good because they need to wear down those ever growing teeth.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Tetraodontiformes
  • Family: Balistidae
  • Genus: Balistapus
  • Species: undulatus
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Maintenance difficulty:

The Undulate Triggerfish or Orange-lined Triggerfish is easy to keep. Triggers are among the hardiest of all marine fish.


Feed all kinds of live, frozen, and flake foods. Best to feed small amounts several times a day. We generally feed squid, shrimp (the same kind people eat), mussels, and all kinds of chopped up fish.

Habitat: Natural geographic location:

Undulate Triggerfish or Orange-lined Triggerfish are found in the Indo-Pacific: Red Sea south to Natal, South Africa (Ref. 4420) and east to the Line, Marquesan and Tuamoto islands, north to southern Japan, south to the southern Great Barrier Reef and New Caledonia. Occurs in coral-rich areas of deep lagoon and seaward reefs from the lower surge zone to at least 50 meters.


Feeds on a variety of benthic organisms such as algae, echinoderms, fishes, mollusks, tunicates, sponges, and hydrozoans. All kinds of meaty foods including starfish and sea urchins, snails, mussels, calcareous algae, and pieces of passing fish.

Social Behaviors:

Generally this fish is aggressive towards other fish, especially other triggerfish. Has a territorial nature.

Sex: Sexual differences:

Unknown. Eggs laid as one cluster in a shallow excavation on sand or rubble along channels.

Light: Recommended light levels:

No special requirements.


No special requirements. Normal temperatures for marine fish is between 74 and 79 degrees Fahrenheit.

Length/Diameter of fish:

Undulate Triggerfish or Orange-lined Triggerfish adults can grow to 30 cm (12 inches).

Minimum Tank Length/Size:

A minimum 60 gallon aquarium is recommended.

Water Movement: Weak, Moderate, Strong

No special requirements.

Water Region: Top, Middle, Bottom

No special requirements.


This fish is available from time to time.