Blue Cross Back Arowana

fish description – Blue Cross Back Arowana Care Guide ($Scleropages\ formosus$ ‘Blue Cross Back’)

Category	Detail
Scientific Name	$Scleropages\ formosus$ (‘Blue Cross Back’ Strain)
Common Name	Blue Cross Back Arowana, Malaysian Golden Arowana, Dragonfish
Origin	Slow-moving rivers and wetlands (Malaysia, Southeast Asia)
Adult Size	24–35 inches (60–90 cm)
Temperament	Highly Aggressive, Solitary, Territorial Surface Predator
Lifespan	10–20+ years
Care Level	Expert (High financial and maintenance commitment)

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Appearance and Sexual Differences

 

• Short Description: A spectacular, long-bodied fish with very large, metallic scales. The ‘Blue Cross Back’ features scales with a deep, prominent blue shine on the core, framed by a gold rim that extends completely over the fish’s back (the sixth row of scales).
• Coloration: Iridescent blue base with metallic gold crossing the back. Juveniles are less colored; the metallic sheen intensifies dramatically with age, diet, and water quality. Sexing is impossible until maturity; the best method is to vent the fish or observe paternal mouthbrooding (males guard the eggs).
• Fins: Long, prominent pectoral fins; dorsal and anal fins are located far back on the body.
• Behavior: Highly intelligent, interactive, and fiercely territorial. They are surface predators and are famous for being powerful jumpers, requiring an extremely secure, weighted lid. They spend the day lurking among roots and branches.

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Tank Requirements and Water Parameters

 

• Minimum Tank Size: 250 gallons (950 liters) is the absolute minimum for a single adult. Custom-built tanks of 8–10 feet in length are highly recommended. The tank must be long and wide.
• Schooling: Must be kept solitary or with extremely large, robust tank mates that occupy the bottom level. Aggression toward conspecifics (other Arowanas) is extremely high.
• Temperature: Tropical range: $75^\circ$–$86^\circ\text{F}\ (24^\circ$–$30^\circ\mathrm{C})$ (stability is paramount).
• pH Level: Soft, slightly acidic water: 6.0 to 7.5 (ideal for Blackwater species). Requires massive filtration (sump and/or large canister filters) and large, frequent water changes (30–50% weekly) to manage the high waste output.
• Aquascape: Keep sparse to maximize open swimming space, which is critical. Use heavy, securely anchored driftwood and bogwood to provide cover and a natural blackwater aesthetic. Floating plants can help diffuse light. The lid must be gap-free and extremely heavy.

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Diet and Feeding

 

The Asian Arowana is a carnivore and a surface predator.

• Staple Diet: Should be fed a high-quality, floating carnivore pellet or stick formulated for Arowanas as the base diet.
• Supplementation: A rich, high-protein diet is essential for color development. Offer live or frozen foods regularly: Prawns (Krill, Mysis), Crickets, Large Mealworms, and Pieces of Fish Fillet. Avoid fatty meats and feeder fish unless rigorously quarantined.
• Schedule: Juveniles should be fed 2–3 times daily; adults should be fed once daily or every other day. Feed only what is consumed immediately at the surface.

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Compatibility

 

• Caution: Extremely aggressive and predatory. Will eat any fish it can fit in its large mouth. Requires caution with all tank mates. Prone to Droop Eye (eye tilts downward) from looking down at sinking food—feed floating food exclusively.
• Good Tank Mates: Only suitable with large, armored, or bottom-dwelling monster fish. Examples include Large Bichirs, Datnoids, large Catfish (e.g., S. petricola, Raphael), and large L-number Plecos. Tank mates must be able to withstand the Arowana’s size and temperament.