Care guide · Freshwater · fish
Marlier's Julie care guide
Julidochromis marlieri
Marlier’s Julie (Julidochromis marlieri) is a large, rock-dwelling cichlid from Lake Tanganyika. It moves close to stones and defends caves and crevices. Its adult size and territorial behaviour require more space than smaller julies: Seriously Fish recommends an aquarium about 120 cm long and 110 litres for a pair. Arrange stable rock piles, shelters, sand and good oxygenation. Keep an established pair where possible, and do not mix Julidochromis species or geographic forms because they may hybridise. Observe pair formation and separate surplus juveniles before territories become contested.
Plan your aquarium →At a glance
- Temperature
- 23–27 °C
- pH
- 7.5–9.5
- GH
- 10–25 °dGH
- Aquarium length
- At least 120 cm
- Minimum aquarium volume
- At least 110 L
- Adult size
- Up to 15 cm
- Group size
- At least 2 individuals
- Temperament
- Territorial
About this species
The species was described as Julidochromis marlieri Poll, 1956 and belongs to the Cichlidae. Its checkered or striped pattern varies between individuals; common English names include Marlier’s Julie and chequered Julie. Seriously Fish gives a maximum standard length of 15 cm. Standard length excludes the tail fin, so it should not be compared directly with total-length figures from other sources. This fish grows considerably larger than transcriptus or ornatus and needs a more spacious bottom area.Natural habitat
Julidochromis marlieri is endemic to Lake Tanganyika. It inhabits rocky shorelines, including deeper water, and is described mainly from the lake’s northern and southern ends, with patchier occurrence along other shores. Rocks provide grazing surfaces, shelter and territory boundaries. In the aquarium, use several secure rock piles with caves and visual barriers. Sand and well-oxygenated water suit the biotope. Make sure heavy stones cannot topple if fish dig beneath the decor.Aquarium and layout
Seriously Fish specifies an aquarium of 120 × 30 × 30 cm, about 110 litres, for one pair. This is not a stocking recommendation for a group: the same source says adult groups require a much larger aquarium. Length and floor space matter because the fish defend caves and rock zones. Build several separate rock piles and keep passages clear. Secure stones on the base, use sand and provide strong but non-disruptive circulation and oxygenation. Avoid pairing two randomly selected adults; where possible, let young fish form a pair naturally.Water conditions
The Seriously Fish maintenance ranges are 23–27 °C, pH 7.5–9.5 and GH 10–25 °dGH. Keep conditions stable and check them with reliable tests. The source separately gives about 25–26.5 °C and pH 8.2–9 for breeding; these are breeding values, not a reason to keep the aquarium warmer or more alkaline year-round. The reviewed information does not establish a separate KH target. Avoid abrupt adjustments and consider the needs of every aquarium inhabitant.Behaviour and group size
Marlier’s Julie is territorial and can be highly aggressive toward conspecifics. Seriously Fish recommends keeping a pair except in a very large aquarium. An established pair is safer than arbitrarily combining an adult male and female, which can lead to persistent chasing. Provide caves and separate rock zones, but do not assume decor alone prevents conflict. Do not mix it with another Julidochromis species or geographic form because hybridisation may occur. Other fish can only be assessed after checking their size, behaviour, space needs and territory requirements individually.Feeding
Offer a varied diet. Seriously Fish recommends live and frozen foods as a substantial part, alongside a good dried food. Include some vegetable matter such as spirulina or blanched spinach. Feed portions that are eaten promptly and check that both fish reach the food. Remove leftovers trapped between rocks. No exact species-specific product with a verified current offer is linked to this guide, so no product is labelled as a recommended staple.Breeding
The species spawns secretively inside a cave. Seriously Fish advises growing a group of juveniles until a pair forms naturally, which may take a year or longer. An arbitrary adult pair may instead become aggressive and cause injury. The source recommends at least about 120 cm of aquarium length for breeding and describes eggs laid on the wall or roof of a cave. Keep this breeding setup distinct from routine care values. Once a pair forms, other fish must be kept outside its territory. Avoid hybridisation with other Julidochromis species and geographic forms.Keeping with other species
Golden julie care guide
UnsuitableDo not keep with Julidochromis ornatus. Julidochromis species and geographic forms may hybridise; keep them separate to avoid unwanted hybrids. This is a breeding and conservation warning.
View species profile →
Masked Julie care guide
UnsuitableDo not keep with Julidochromis transcriptus. Julidochromis species and geographic forms may hybridise; keep them separate to avoid unwanted hybrids. This is a breeding and conservation warning.
View species profile →Sources & review
This care guide draws on several specialist sources and was last checked on .