1.5–2.0 T/H Koi Carp Feed Extruder Machine in Japan

The decision to purchase a standalone koi carp feed extruder machine in Japan stemmed from a specific production bottleneck. The client already owned a hammer mill, a ribbon mixer, a dryer, and a coating machine used for producing trout and eel feed.

However, their existing single-screw dry extruder could not achieve the necessary expansion ratio or the stability in high-fat formulations required for premium koi feed.

Because koi feed must float for several minutes without disintegrating, and because it often contains 8-12% added fish oil (sprayed post-extrusion), the processing technology must create a highly gelatinized starch matrix.

The client purchased the twin-screw extruder as a single unit to replace their aging dry extruder, integrating it seamlessly with their existing downstream drying and coating line.

This targeted upgrade allowed them to enter the floating ornamental feed market without rebuilding their entire facility, a cost-effective strategy for a specialized product line.

Project Background: The Demands of the Japanese Koi Industry

Japan is the global benchmark for koi carp feed production technology, and for good reason. Koi (Nishikigoi) are not merely pond fish; they are living investments, with individual specimens often valued at tens of thousands of dollars.

The feed must serve multiple functions: promote growth, enhance red (Hi) and white (Shiroji) coloration, support digestion during cold winters, and maintain water clarity in closed-loop recirculating aquaculture systems (RAS).

The client, a feed producer established in the 1980s, observed that their farmer customers were increasingly importing floating pellets from Europe and Southeast Asia. These imports were expensive and suffered from long lead times.

Domestically, while large corporations produced extruded feeds for marine fish, few specialized in the specific "heavy floating" pellet required for koi (which need to stay at the surface for visual feeding enjoyment).

The client needed a koi carp feed extruder machine in Japan that could handle complex, sticky doughs rich in wheat gluten and fish meal while producing pellets with a smooth surface and a consistent length of 4-8mm and diameter of 3-5mm, depending on the fish's growth stage.

The company chose RICHI after evaluating European and local Japanese alternatives. The decision came down to two factors: the ability of RICHI's twin-screw to handle variable raw material moisture levels (wet process) and the superior wear resistance of the barrel and screws, which is critical when processing abrasive ingredients like rice bran and full-fat soybean.

Raw Material Sourcing and Formulation Strategy

A key reason the client shifted to a wet-type extrusion process was the need to incorporate higher levels of fresh, local ingredients. Japanese feed mills prioritize domestic sourcing where possible to reduce the carbon footprint and support local agriculture.

For this specific koi carp feed extruder machine in Japan project, the client formulated three distinct recipes for different growth stages (juvenile, maintenance, and color-enhancing).

According to standard Japanese aquafeed formulation tables, koi diets typically avoid high levels of soybean meal due to anti-nutritional factors that can cause gut inflammation in ornamental cyprinids. Instead, the client uses the following base mix for their high-growth formula:

• Brown Fish Meal (60-65% protein): 18% – sourced from Hokkaido pollock.
• Wheat Flour (as a starch binder): 25% – crucial for expansion; Japanese high-gluten flour is preferred.
• Corn Gluten Meal: 13% – a natural pigment source for yellow/orange enhancement.
• Full-Fat Soybean (Extruded): 26% – adds lecithin for lipid digestion.
• Defatted Rice Bran: 9% – a cheap energy source widely available in Niigata.
• Mineral and Vitamin Premix: 1% – specifically tailored with high Vitamin C and E for stress resistance.

Before purchasing the RICHI extruder, the client struggled with this exact recipe. The high oil content from the full-fat soy and the sticky nature of wheat gluten caused frequent die blockages in their dry extruder.

The wet type fish feed extruder's preconditioner hydrates the starch (30-35% moisture) before it hits the barrel, reducing mechanical friction and allowing for smoother extrusion of sticky doughs.

Equipment Selection: The Wet Twin-Screw Solution

After analyzing the client's production target (500kg to 800kg per hour) and their facility's steam availability, RICHI recommended a specific model from the wet twin-screw series.

The client did not need the massive output of the SPHS185*2, as the koi feed market in Japan is niche. Instead, they selected a mid-range model that balances volume with the flexibility required for a specialty feed mill.

Selected Model for Japan: SPHS120*2 Wet Twin-Screw Extruder

This koi carp feed extruder machine in Japan was configured with a high-shear screw profile. The client specifically requested this because koi feed requires a high "expansion ratio" (the pellet diameter after exiting the die versus the die hole size).

For koi, the pellet must float at 100% for at least 2 hours without absorbing water and sinking. The twin-shear action of the SPHS120*2 gelatinizes the wheat starch effectively, creating a porous yet durable matrix that holds up during vacuum coating with fish oil.

Comparison: Why Wet Twin-Screw Over Single-Screw?

The client's initial inquiry focused on a dry single-screw unit (DGP-120B) because of its lower initial price. However, RICHI's sales engineers demonstrated why wet processing is vital for Japanese koi feed standards.

• Dry Single Screw (DGP-120B): Relies solely on friction for heat. This burns the outer layer of the corn gluten meal, reducing the effectiveness of natural pigments. It also struggles to inject steam into the "soggy" mixture required for koi.
• Wet Single Screw (DSP-135B): Better than dry, but lower production stability. The Japanese client had previous negative experiences with single-screw "cogging" (uneven torque) when processing high-fat recipes.
• Wet Twin Screw (SPHS120*2): The client chose this because it offers "self-wiping" screws. This means almost all material is moved forward uniformly, eliminating burned spots and providing a uniform gelatinization degree of 95%+, which is critical for the fragile digestive systems of prize koi.

Shipping and Logistics to Japan

Given the size of the SPHS120*2 (the main motor alone weighs several tons), transportation was a critical phase. The machinery was manufactured at RICHI's headquarters in Shandong Province, China. From there, it was loaded onto a flat rack container and shipped from Qingdao Port, one of the busiest and most efficient ports in Northern China.

The standard sea route took approximately 2 to 3 days. The designated arrival port for this shipment was Port of Yokohama. Yokohama is a major hub for agricultural imports and is geographically close to the client's production facility in Niigata, minimizing inland freight costs.

Upon arrival, RICHI arranged for customs clearance support, ensuring the electrical components (configured to Japan's strict 200V/50Hz grid standards) passed inspection without delays.

Operational Benefits and Production Flexibility

Since commissioning the koi carp feed extruder machine in Japan, the client has expanded their product portfolio beyond just koi feed. This versatility was a major selling point for RICHI. The machine's robust construction and wide processing window allow the manufacturer to produce three distinct product categories without changing the core screws, just by altering the die plate and cutter speed:

1. Sinking Fry Feed (0.5-1.2mm): For juvenile koi and goldfish. The twin-screw configuration allows for high density (low expansion) by adjusting the water injection rate in the barrel.
2. Floating Pond Koi Feed (3-8mm): The main product. The material is superheated and expanded as it exits the die.
3. Soft-Moist Cat Treats (Pet Food): A new business line for the client. By reducing the drying time post-extrusion and using the same SPHS120*2, they now produce high-end dog and cat snacks for the Tokyo pet market, a sector that grew 15% last year.

RICHI's Technical Support and Global Expertise

When the client asked, "Why should we trust RICHI with such a specialized machine for the Japanese market?" the answer lay in RICHI's extensive track record with extruded aquafeed solutions.

The sales team provided case studies from similar high-standard markets, including the successful installation of a SPHS150*2 in Scotland for salmon feed and a SPHS75x2 in Chile for trout feed.

While the Japanese client was the first to order this specific model for ornamental fish in Japan, RICHI has exported extrusion lines to over 100 countries, including the Netherlands for pig feed concentrates and Bulgaria for fishmeal processing.

To ensure the SPHS120*2 fish feed extruder performed flawlessly, RICHI flew a senior extrusion technician to Niigata for 15 days. The service provided included:

• On-site assembly supervision: Ensuring the gearbox alignment was perfect to prevent vibration on Japan's seismic flooring.
• Training on Die Design: The client was taught how to calculate "die land length" versus "hole diameter" to control pellet buoyancy specifically for koi winter feeding.
• Raw Material Analysis: RICHI tested the client's rice bran and wheat flour for fat absorption index (FAT) to adjust the cutter speed, ensuring every pellet was exactly 4mm long with no "tails" or rough edges.

Marketing Edge for the Client

With the new koi carp feed extruder machine in Japan, the client launched a new product line branded "Niigata Float." They market it specifically as "Twin-Screw Extruded," using the technology as a selling point to breeders.

Because the machine can inject steam and precisely control retention time (via the differential conditioner), the feed has a distinct aroma of cooked rice and fresh fish—a smell that triggers strong feeding responses in koi.

Furthermore, the water stability of the pellet (over 24 hours without disintegration) has significantly reduced filter changes for koi hobbyists, saving them thousands of dollars annually in maintenance.

Conclusion

Investing in a specialized koi carp feed extruder machine in Japan allowed this Niigata-based producer to stop importing floating feeds and start dominating the local ornamental market.

By choosing the RICHI SPHS120*2 wet twin-screw extruder, they overcame the technical hurdles of high-fat, high-starch formulations. The result was a 40% increase in their profit margin on koi feed within six months, simply because they could now control the quality, color, and floatation time of every pellet.

For any aquafeed producer in East Asia looking to upgrade from a simple grinder-mixer setup to a professional extrusion line, RICHI Machinery provides the hardware and the technical extrusion know-how to make it profitable.