Max Size: 4cm

Blue Purple Emperor Tetra (Inpaichthys kerri)

Blue Emperor Tetras are active peaceful shoaling fish. Unfortunately, Blue Emperor Tetras do have a somewhat undeserved reputation for fin-nipping. However, this type of behaviour only really manifests if you do not keep them in sufficient numbers and there are not enough visual barriers amongst the decor.

You should always maintain this species in good-sized groups of around ten or more individuals. Not only will this make the fish feel more secure, but it will result in far less hostility between the males, and it will create a much more effective and natural-looking display. In addition, rival males will show their best colours when displaying at one another.

Ideal tankmates for Blue Emperor Tetras should be small and peaceful. These could include Corydoras Catfish, small Dwarf Cichlids such as Mikrogeophagus or Apistogramma, Pencilfish, and some smaller suckermouth Catfish. These fish will also do well with Rasboras, smaller Gouramis and peaceful Barbs. It would be better to avoid larger, more boisterous tankmates as these Tetras are easily intimidated. You must pay much attention to water quality because Blue Emperor Tetras can be sensitive to high nitrate levels and fluctuations in water chemistry.

The best aquarium setup for these Tetras would include plenty of driftwood. This will create shady areas for your fish and gradually release tannins from the wood, which will help acidify the water whilst giving it a natural, clear tea colour. Peat filtration can also help in this regard. Although plants are not found in abundance in this species natural waters, a moderate amount of planting will be appreciated and will help make the fish feel more secure. Lighting should not be too bright, and a darker substrate and background will help show off their pleasant colours.

Male and female Blue Emperor Tetras differ in colouration. The male's entire bodies are light purplish-blue except for their stomachs which are beige. In addition, they possess a thick iridescent dark blue stripe that extends from the snout through to their eye and the caudal fin. The male's dorsal fin is elongated, and their adipose fin is blue. The other fins are transparent except for the pectoral and anal fins that also have a hint of blue.

In comparison, females also have an elongated dorsal fin; however, their adipose fin is usually a reddish orangy brown. The females also possess a thick black line instead of blue, and the area above it is beige with a silvery-blue sheen. In addition, the belly is white and occasionally has a silvery sheen, and its fins are transparent.

Tank Mates for the Blue Purple Emperor Tetra

1 ideal tank mate ideas for the Blue Purple Emperor Tetra include:

Cardinal Tetra(Paracheirodon axelrodi)
Quick Facts
Scientific NameInpaichthys kerri
Other NamesBlue Emperor Tetra, Royal Tetra, Blue Kerri Tetra, Purple Emperor Tetra, Regal Teta
Aquarium LevelMiddle - Top
Best kept asGroups 10+
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH6.0 - 7.5
GH3 - 12
73 - 79℉
22.8 - 26.1℃

Photos of the Blue Purple Emperor Tetra

Blue/Purple Emperor Tetra
Blue/Purple Emperor Tetra
Blue/Purple Emperor Tetra

Natural Habitat

The Blue Emperor Tetra is endemic to the Aripuana River, which shapes part of the upper Madeira River Basin in Mato Grosso, north-western Brazil in South America. They inhabit soft and acidic sluggish tributaries where the waters are clear but stained a brown colour due to the tannins being released from decaying leaves falling from the forest canopy above.

Madeira river tributary

What to feed the Blue Purple Emperor Tetra

Blue Emperor Tetras are not fussy and have no special requirements for food. They will accept most dried foods like flakes, granules and pellets; however, you should also offer them frequent meals of small live and frozen fares such as bloodworm, white mosquito larvae, daphnia and brine shrimp. A varied diet will guarantee your fish have the best colour and will help with their development.

How to sex the Blue Purple Emperor Tetra

It is relatively straightforward to distinguish male from female Purple Emperor Tetras. Mature males are usually more colourful and of a slimmer build, are larger and have a rounded anal fin. In contrast, females are far less bright, stockier in body shape than males and have an angular anal fin.

How to breed the Blue Purple Emperor Tetra

Blue Emperor Tetras have been spawned regularly in the aquarium hobby. However, you will need to set up a separate breeding tank if you would like to raise a decent number of fry.

The Breeding tank will need to be dimly lit and contain bundles of fine-leaved plants such as java moss so that the fish have somewhere to deposit their eggs; spawning mops will work just as well. Alternatively, you could cover the bottom of the tank with some mesh that has large enough holes to allow the eggs to fall through but small enough holes so the adults cannot reach them. The water in the breeding tank will need to be soft and acidic, and the temperature needs to be slightly higher than their usual aquarium. A small air-powered sponge filter slowly bubbling is all that is required when it comes to filtration.

You can spawn these Tetras in a group, with half a dozen individuals of each sex being ideal. However, you will need to condition them with plenty of small live and frozen foods first, then spawning should not bestow too many problems.

Alternatively, you can spawn these Tetras in pairs. You will need to condition the fish with live and frozen foods in female and male groups in separate tanks to achieve this. Then, once you notice the females are full of eggs and the males are displaying their best colours, choose the fattest female and the best-coloured male and transfer them to the breeding tank in the evening. The Tetras should then spawn the following morning.

Whichever method you choose, the adults will eat the eggs if given a chance, so you should remove them from the tank as soon as you spot any eggs.

The eggs will usually hatch between 24 and 48 hours later, and the babies will become free swimming 3 to 4 days after that. Therefore, it would be best to feed the fry with infusoria type foods for several days until they become large enough to accept microworm or baby brine shrimp.

Other Tetras of interest

African Moon Tetra(Bathyaethiops caudomaculatus)
African Red Eyed Tetra(Arnoldichthys spilopterus)
Black Darter Tetra(Poecilocharax weitzmani)
Black Line Tetra(Hyphessobrycon scholzei)
Black Neon Tetra(Hyphessobrycon herbertaxelrodi)
Black Phantom Tetra(Hyphessobrycon megalopterus)
View all Tetras
Date Added: 29/07/2021 15:46:48 - Updated: 22/11/2021 16:59:24