Silver Arowana Care Guide: Osteoglossum Bicirrhosum in Singapore
The silver arowana is the gateway species for many monster fish keepers, a sleek, powerful predator that commands attention in any room. This silver arowana care guide from Gensou Aquascaping at 5 Everton Park, Singapore addresses the practical realities of housing Osteoglossum bicirrhosum in our tropical climate. Reaching up to 90 cm in captivity, silvers demand serious tank space and long-term commitment, but their graceful surface patrol and explosive feeding strikes make them unforgettable centrepiece fish.
Understanding the Silver Arowana
Osteoglossum bicirrhosum originates from the Amazon basin, where it inhabits slow-moving rivers and flooded forests. Two barbels extend from the lower jaw, serving as sensory organs to detect surface vibrations. Unlike the regulated Asian arowana, silvers require no CITES permit or microchip in Singapore, making them freely available and significantly more affordable. Juveniles as small as 10 cm appear regularly in local shops.
Tank Size and Structural Considerations
A juvenile silver fits comfortably in a 300-litre tank, but adults need a minimum of 1,000 litres with a tank length of at least 180 cm. Anything shorter forces the fish to constantly turn, leading to spinal deformities. Width matters too: 60 cm front-to-back is the bare minimum, with 75 cm preferred. For HDB residents, a tank this size filled with water, substrate and hardscape can weigh over 1,200 kg. Position it along load-bearing walls and consult an engineer if your flat is above the ground floor.
Secure the lid with weights or clips. Silver arowanas are notorious jumpers, capable of launching themselves clear out of open-top tanks. A single unsecured feeding hatch is enough for an escape attempt.
Water Parameters
Singapore’s PUB tap water, once treated for chloramine, provides a reasonable starting point. Silvers prefer a pH of 6.0 to 7.0, a temperature of 26 to 30 degrees Celsius and soft to moderately hard water. Weekly changes of 25 to 30 per cent maintain nitrate levels below 20 ppm. A large sump filtration system with biological, mechanical and chemical stages handles the substantial bioload. Avoid drastic parameter swings during water changes, as arowanas are sensitive to sudden shifts.
Feeding for Healthy Growth
Juveniles under 20 cm do well on a varied diet of bloodworms, small crickets and high-protein pellets such as Hikari Arowana Sticks. As the fish grows, introduce market prawns with shells removed, smelt, and the occasional earthworm. Limit feeder fish, which carry parasites and offer poor nutritional value compared to prepared foods. Feed juveniles twice daily, sub-adults once daily and mature adults every other day.
Overfeeding is a common mistake. A slightly concave belly before feeding time indicates good condition. A constantly round belly suggests too much food, which accelerates fatty liver issues and shortens lifespan.
Preventing Drop Eye
Drop eye, where one or both eyes angle permanently downward, is the most discussed health concern among arowana keepers. The exact cause remains debated, but contributing factors include fatty deposits behind the eye, constantly looking downward for food and reflections on the tank bottom. Preventive measures include feeding from the surface rather than mid-water, using a dark or opaque bottom panel, keeping the tank above eye level and maintaining a lean diet. Once established, drop eye is very difficult to reverse without surgical intervention.
Compatible Tank Mates
Silver arowanas coexist with other large, robust species that occupy different water zones. Datnoids, large plecostomus such as Pterygoplichthys, peacock bass and Geophagus eartheaters work well. Stingrays are a popular pairing in Singapore’s monster fish community. Avoid smaller fish, which become expensive live food, and overly aggressive species like large flowerhorns that may damage the arowana’s delicate scales and barbels.
Growth Rate and Lifespan
Under optimal conditions, a silver arowana grows roughly 5 cm per month during its first year, slowing considerably after that. Most reach 60 to 75 cm within three years. Lifespan in captivity is 10 to 15 years with proper care. Plan your setup for the adult size from day one. Upgrading tanks multiple times is stressful for the fish and expensive for the keeper.
Purchasing in Singapore
Juvenile silvers cost as little as $10 to $20 at fish farms along Pasir Ris Farmway and shops in the Serangoon North area. Larger specimens of 30 cm or more range from $40 to $80. Select fish with straight spines, intact barbels and clear eyes. Avoid individuals with kinked bodies or cloudy eyes, as these issues rarely resolve with age. Transport the fish in a large bag with minimal air space to prevent jumping injuries during the journey home.
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