Bighead carp

Water parameters

Minimum tank: 4000 L per individual at harvest size.

Feed and growth

Feed protein

25% target

Daily feed (warm)

2.50% of body weight

Daily feed (cool)

0.70% of body weight

Max density

40 g per litre

A 40000 g adult eats about 1000.0 g of feed per day at optimum. 10 fish at adult size: ~10000 g daily.

Legality

Rules vary by jurisdiction and change over time. Verify with your local fisheries or wildlife authority before stocking.

Unlisted jurisdictions default to "check local regulations".

Origin and habitat

Hypophthalmichthys nobilis is native to the large rivers of eastern Asia, mainly central and southern China, including the Pearl and Yangtze systems. It is a filter feeder, straining zooplankton and the larger phytoplankton from the water with long, flat gill rakers; it has no true stomach and feeds almost continuously, taking in a large share of its body weight in plankton each day. Paired with silver carp, which filters finer phytoplankton, bighead carp anchors the traditional Chinese polyculture that has produced fish for well over a thousand years. It is one of the most heavily cultured fish in the world, with output on the order of three million tonnes a year, nearly all of it in China, and it has been moved to many countries for food and for plankton control in ponds and lagoons. That history has a dark side: bighead carp brought to Arkansas in the 1970s for water-quality work escaped into the wild, and together with silver, grass, and black carp, the group sold as 'Asian carp', it has become one of the most damaging invaders of the Mississippi basin, crowding out native filter feeders and reworking food webs. A large fish, it reaches around 120 cm and can top 40 kg.

Climate and outdoor ponds

Climate

temperate (handles seasonal swings)

USDA zones

5–12 (winter low around -29°C or warmer)

Heating needed

no

Cooling needed

no

Care notes

A filter feeder that lives on plankton rather than prepared food, so it makes little use of pelleted feed and is raised instead as a low-input, non-fed species in fertile water. It needs systems that grow plenty of plankton, fertilized ponds, lakes, or big nutrient-rich water bodies, which makes it a poor fit for ordinary aquaponics, where the aim is clean, well-filtered water with few suspended solids. In Chinese polyculture it takes the zooplankton niche alongside silver carp (phytoplankton), grass carp (water plants), common carp (bottom detritus), and often tilapia or catfish, with the species partitioning the pond's food. Growth in productive water is fast, reaching 1–3 kg in twelve to eighteen months. The fish is eurythermic, surviving from near freezing to about 38 C, but it feeds and grows in the 15–30°C band and does best around 25–28°C, spawning when river temperatures climb to roughly 25 C after spring floods. In the United States, culture is heavily restricted or banned in most states because of the invasion of the Mississippi basin; bighead carp was added to the federal Lacey Act injurious wildlife list in 2011, making it illegal to import or move live fish, eggs, or hybrids across state lines without a permit, and agencies work to keep it out of the Great Lakes. Where it is legal and ecologically appropriate, mainly China and Southeast Asia, it is a high-volume, low-input protein source. It is not a sensible aquaponics choice anywhere with invasive-carp rules.

Further reading

• Aquaponics water chemistry: balancing pH for fish and plants
• Fish for aquaponics: tilapia vs everything else