Chaetodon triangulum

Download Reef App on Google Play or App Store
Get it on Google Play Get it on App Store
Facts
Latin name Chaetodon triangulum - Cuvier, 1831
Local name Triangle butterflyfish
Family Chaetodontidae - Chaetodon
Origin East Indian Ocean, West Indian Ocean, Japan, The Red Sea, Indonesia
Max length 16 cm (6,3")
As aquarium fish
Minimum volume 400 cm (106 gal)
Hardiness Average
Suitable for aquarium Experience, preparation and extra care required
Reef safe Not reef safe
Aggressiveness Might be aggressive towards food competitors
Feed
Recommended Larger crustaceans (Shrimp, crabs...)
Other invertebrates
Soft coral
Large polyp stone coral (LPS)
Small polyp stone coral (SPS)
Beware of
Can nibble at clams

This species sometimes nibbles at clams including Tridacna species.

Territorial towards its own species

In captivity this species will attempt to make its own little territory. It can therefore be very aggressive towards species of the same family, when not provided with sufficient space.

Feeding problems

These fish normally eat for the most part, coral polyps, therefore problems can arise in captivity when trying to give it an alternative food.

It is therefore essential to be well prepared before acquiring them and have several suitable food types ready to present them with.
However well prepared, there will be a large percentage, that will die after a short time in captivity.

It may mean having to keep living corals, mussels and zooplankton as food, in order to keep these fish alive whilst they are getting accustomed to alternative types of food.

Keep in mind
Requires a varied diet

This species must be fed with an appropriately varied diet.

Frequent feeding

This fish requires feeding several times a day, especially when newly added.

When the fish can find its natural food in the aquarium it requires less frequent feeding. 

Hiding places

This species needs good hiding places, for example, between live rocks.

Requires plenty of space for swimming.

This species revels in swimming and requires an aquarium with ample space.

Descriptions and further reading
Genus description (Chaetodon)

Some species of the Chaetodon genus are grouped together in what is known as a "complex", since they are so very similar.

Regardless of resemblance, it is important to be able to distinguish them, as in some cases they vary greatly in their needs. Sometimes there are just small differences in colour or pattern, but in other instances it is vital to know where the fish originally come from.

Family description (Chaetodontidae)

The Butterflyfish are known for their attractive patterns and colours. They are closely related to Angelfishs, but can always be distinguished, as they lack the spines on each side of the head of the Angelfish.

A smaller group of these fish will seek out primairily soft corals, like Zoanthus. A larger part of the species will target different types of LPS corals. Butterflyfish are also known to seek out anemones, tubeworms and bristleworms.

Therefore it is important to choose the correct species in relation to the corals wanted, if one desires to keep Butterflyfish in a coral-aquarium.
Bristleworms, tubeworms and other small invertebrates are also a part of the diet for many Butterflyfish.

It can be problematic, with many of these species, to get them eating in the beginning, but many of the species cannot resist live zooplankton or live mussels with crushed shells. Another option is to mimic their natural behaviour by stuffing their food into coral skeletons or stones.

They ignore most other fish and are generally peaceful, therefore multiple Butterflyfish will have no problem living together. One should however be cautious about keeping similar species together unless they are a couple.

As these fish can be difficult to acclimatize and get feeding, it is important to buy healthy fish, to avoid having to deal with more problems. Make sure to check that they do not have parasites or any visible infections.

There are some species that should not be kept in an a aquarium, as they are food specialists and will almost always refuse to eat replacement foods. It can be possible to breed some species, which will eat frozen foods. Otherwise the only way to keep food specialists is by feeding them their natural diet, which consists of live SPS or LPS corals for example.

FishBase
Aquarium trade Yes
Distribution Indian Ocean: Madagascar to the Andaman Sea (Ref. 9710) and western sector of the Indonesian Archipelago.
Danish common names Trekanthalet fanefisk
German common names Triangelfalterfisch
French common names Papillon triangulaire indien
Chétodon à chevrons
References and further reading

About references

Bob Fenner. Corallivorous Butterflyfishes… For Aquariums? - Wet Web Media - (English)

Scott W. Michael. 2004. Angelfishes and Butterflyfishes (Reef Fishes Series Book 3) TFH Publications / Microcosm Ltd. - (English)
Bob Fenner. Butterflyfishes; Separating the Good Ones and Those You Don't Want - Wet Web Media - (English)
Collection of links to additional information - Wet Web Media - (English)
Tea Yi Kai. 2014. Reef Nuggets 2: Aquatic Lepidopterans for your reef (Revised edition) - Reef Builders - (English)