Encyclopaedia
Marlier's Julie
Julidochromis marlieri
The 'Checkerboard Submarine' of the African Rift. A wildly unique, cigar-shaped cichlid (13 cm / 5 inches) that acts like a gecko, swimming belly-flat against rocks, and often hovering completely upside down beneath cave ceilings. They form fiercely loyal monogamous pairs that will aggressively slaughter any other of their kind in the tank.
- Family
- Cichlidae
- Origin
- Africa (Endemico del Lago Tanganica)
- Origin
- Africa and Madagascar
- Tank use
- Used in 0 tanks
Share
23 °C - 27 °C
8 - 9
Freshwater
Bottom
13 cm
Description
Geographic Origin and Biotope: Broadly distributed among the rocky rubble zones and steep submerged cliffs of the northern, western, and southern shores of Lake Tanganyika. They never venture into the open, sandy abyss, spending their entire lives slithering through the darkest, tightest cracks between the boulders.
Taxonomy and Morphology: One of the thickest and largest members of the famous Julidochromis ('Julie') genus. Reaches about 13 cm (5+ inches). The body shape is spectacular: hyper-elongated, tubular, and cylindrical like a submarine or a fat cigar. The snout is sharply pointed. The dorsal fin runs the absolute entire length of the back like a low sail. This torpedo shape allows them to navigate insanely tight cracks and navigate backwards out of blind tunnels.
Social Behavior: Incredible, almost alien bio-mechanics. They have an instinctual behavior where their belly must always face the nearest solid object. If they swim near a vertical cliff, they swim perfectly sideways; if they enter a horizontal cave, they flip and swim perfectly upside down along the ceiling. They are incredibly secretive and stealthy. When a male and female pair bond, they become an unstoppable force, aggressively claiming a massive rock pile and viciously hunting down and executing any other Julies in the aquarium.
Coloration and Sexual Dimorphism: A stunning, high-contrast geometric masterpiece. The base body is pale cream or creamy-white, completely engulfed in an intricate, complex checkerboard grid of thick black horizontal stripes and crossing vertical bars. The edges of the dorsal, tail, and anal fins are stunningly trimmed in a glowing, iridescent neon blue line. Sexual dimorphism is virtually non-existent; males and females look exactly identical, though strangely for cichlids, the Alpha female is often slightly thicker and larger than the male.
Care and observations
Tank Setup: A 100 cm (40-inch / 40-55 gallon) tank is required for a single bonded pair. THE ROCKWORK IS EVERYTHING. You must construct an intricate, massive mountain of flat slate, limestone, or holy rock piled high, explicitly ensuring there are dozens of incredibly tight, dark, blind crevices and caves (1 inch wide gaps are their favorite). THE LETHAL WARNING: Once a pair bonds and claims a rock pile, NEVER REARRANGE THE ROCKS. If you move their rocks during cleaning, the 'bond' instantly shatters, they stop recognizing each other, and the stronger one will violently murder its partner overnight in a territorial panic.
Feeding: Micro-Predator / Omnivore. In the wild, they pick tiny crustaceans and sponges out of the rock cracks. Feed high-quality sinking cichlid pellets or finely crushed flakes. They greedily demand frozen and live foods: heavily supplement with frozen Mysis shrimp, brine shrimp, and bloodworms. They will cautiously dart out of the rocks, grab a mouthful of food, and instantly reverse backwards into their cave to eat it safely.
Water Quality: Tanganyika chemistry. Rock-hard, highly alkaline water. pH 8.0-9.0. High GH/KH buffer. Temp 24-27°C (75-80°F). They are highly sensitive to sudden fluctuations in temperature and massive chemical shifts. Perform small, frequent water changes rather than massive 80% drains to avoid shocking the pair into breaking their bond.
Compatibility: THE 'PAIR AND CULL' RULE. Do not buy two random Julies. Buy a group of 6 juveniles. Let them grow up together until two pair off and claim a rock cave (you'll notice them attacking all the others). You MUST immediately net out and return the other 4 'singles' to the store, or the bonded pair will murder them one by one. A bonded pair can peacefully co-exist in large tanks with totally different fish, like upper-water Cyprichromis, Shell-dwellers (Multies), or large Altolamprologus, as long as the other fish don't enter their rocks.
Reproduction: Extremely secretive Cave Spawners. They DO NOT hold eggs in their mouth. The pair will retreat into the deepest, darkest, most inaccessible 1-inch crack in the tank (usually on the ceiling, upside down) and glue 40 to 100 green sticky eggs to the rock. You will never see the eggs. Weeks later, you will simply notice tiny, 3mm long, fully formed checkerboard replicas slithering flat against the rocks. The parents are amazing: they allow multiple successive generations of fry to live together in the same cave simultaneously.
Risks: 1. THE DIVORCE MURDER: The most common tragedy is the owner moving the rocks in the tank to clean, shattering the pair bond, resulting in the male or female murdering their lifelong partner. 2. Massacre of un-bonded juveniles if left in the tank after the Alpha pair forms. 3. Fatal hybridization: NEVER mix two different species of Julidochromis (like J. transcriptus and J. marlieri) in the same tank, or they will interbreed creating ugly 'mutt' fish.
Fish profile
- Temperament
- Territoriale, calcolatore ma schivo verso pesci di media taglia. Sono ferocemente intolleranti verso gli altri membri della propria specie o pesci con forma simile che cercano di rubargli i nascondigli. Vivono e muoiono per difendere la loro grotta.
- Diet
- Onnivoro. In natura spizzicano invertebrati ('Aufwuchs') dalle pareti verticali delle rocce. In acquario accettano di tutto, ma la dieta ideale è un mix equilibrato: fiocchi/granuli di alta qualità con aggiunte bi-settimanali di vivo o surgelato (Artemia, Daphnia). Hanno bocche piccole posizionate sotto al muso per "brucare".
- Tank level
- Bottom
- Minimum group
- 4
- Adult size
- 13 cm
- Minimum tank
- 120 L
- GH
- 10 dGH - 25 dGH
- KH
- n/a
- TDS
- n/a
- Conductivity
- n/a
- Sex ratio
- Coppia Fissa Monogama (Si compra un gruppo di 4-6 giovani). A differenza dei poligami del Malawi, formano coppie saldissime per la vita. Quando si forma una coppia in vasca, elimineranno sistematicamente tutti i loro fratelli, quindi è necessario isolare i due amanti felici. Dimorfismo assente, solo la papilla genitale li distingue in età adulta.
- Feeding frequency
- 1-2 volte al giorno. Sono lenti mangiatori e si nutrono vicino alle rocce, quindi assicuratevi che il cibo raggiunga le loro tane prima di essere divorato da eventuali compagni più voraci di superficie.
- Bioload
- Basso-Medio.
- Flow
- Corrente da Moderata a Lieve. Si muovono strisciando lungo le rocce, fuggendo le forti correnti d'acqua libere.
- Reproduction
- Substrato-deponenti da fessura (Grotte). Non vedrete mai le uova: la femmina le incolla capovolte nel punto più irraggiungibile di una grotta strettissima, a testa in giù. I due genitori (spesso la femmina dentro e il maschio di guardia all'ingresso) formeranno un fortino letale. Covate piccolissime (spesso sotto i 40 piccoli), ma curatissime. Spesso si vedono più generazioni di minuscoli avannotti coesistere.
- Compatibility
- Mantenimento Specializzato. Ottimi in vasche di comunità Tanganica PURCHÉ ci siano montagne di rocce isolate per spezzare i territori visivi. Convivenza eccellente con i Neolamprologus brichardi (che occupano rocce diverse), Altolamprologus calvus e Cyprichromis (che stanno in superficie). MAI inserire più specie di Julidochromis nella stessa vasca: il rischio di incroci letali e risse a morte è garantito.
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.

