Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Julidochromis transcriptus

Masked juli

Julidochromis transcriptusJulidochromis transcriptus
Photos by Andy Rapson


Julidochromis: Taken from marine wrasse "julidini"; also from Greek, ioulis = a fish dealing with genera Coris or Thalassoma.

General Notes:

J. transcriptus is a very aggressive and territorial fish particularly towards its own kind. The pair bond between male and female is quite fragile and over disturbance during tank maintenance may cause fighting amongst even well established pairs with the male almost always coming off worse. Keep only one pair per tank unless the tank is very large and has at least two separate rocky reefs. J. transcriptus can be kept with other non-competing fish from different niches in Lake Tanganyika such as shell dwellers or open water species like Cyprichromis. They are not suitable for a general community tank due to the water chemistry of a very high pH and mineral rich water that J. transcriptus needs in order to thrive.


In the wild J. transcriptus is a micro predator feeding on small crustaceans, worms and insect larva. In captivity they will accept a good quality flake food which must be supplemented with small live or frozen food such as cyclops, daphnia, brine shrimps, blood worms and glass worms.


Adult females are larger than the males. Females are normally dominant.


J. transcriptus doesn't require any special preparation. Well cared for fish will pair up, claim their territory and spawn of their own accord. They are so secretive that you may not even realise that they have spawned until you see Juli fry swimming around their parents territory. They make excellent parents and their territory is normally quite inaccessible so even in a community tank most fry will survive. However once they reach a certain size they will be regarded as competitors and intruders and attacked. When removing some well grown fry it is very important not to disturb the pairs territory or you risk splitting the pair bond of the adult fish. Only remove the fry which become accessible. Once a pair begin spawning they are very prolific and it isn't uncommon for them to spawn whilst still caring for very small fry from the previous brood.

Wild status

IUCN Red List of Threatened Species lists J. transcriptus as least concern. The species is widespread and common in the northern part of Lake Tanganyika and is under no immediate threat.

Information at a glance

pH: 8.6 - 9.5
dGH: 11 - 17
Temperature: 22 - 25°C (72 - 77°F)
Diet: Micro predator
Size: 7cm (3in)
Min tank size: 60 litres
Difficulty level: difficult
Aquarium type: Community
Swimming level: close to rocks

Distribution and habitat

distribution map for Julidochromis transcriptus

Origin: Africa: Endemic to the northwest shore of Lake Tanganyika, between Luhanga and Makabola (Democratic Republic of the Congo)

Habitat: Always very close to rocks.


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Cichlidae
Genus: Julidochromis
Species: J. transcriptus Matthes, 1959

Common name:
Masked Juli

Synonyms: None