The fundamental distinction between floating and sinking feeds lies in their manufacturing processes. Floating feed is produced through high-temperature, high-pressure extrusion expansion. In this process, raw materials are heated to above 120°C inside an extruder. Under high pressure, the starch undergoes gelatinization. When the mixture is extruded, the sudden pressure release causes moisture to vaporize instantly, forming a porous structure. This reduces the density of the feed to below that of water, allowing it to float.
In contrast, sinking feed is manufactured using conventional pelleting. The raw materials are pressed into shape at lower temperatures, typically between 60°C and 90°C, resulting in dense, non-porous pellets that sink quickly when immersed in water.
Floating fish food
The extrusion process can degrade certain heat-sensitive nutrients, such as vitamins. Therefore, floating feed often requires the addition of nutrient packs after processing. On the other hand, sinking feed retains nutrients more effectively but usually necessitates binders to prevent disintegration. Additionally, due to its porous structure, floating feed absorbs water and softens more easily. This characteristic suits the surface-feeding habits of koi and makes it convenient to monitor feeding activity. Sinking feed is more suitable for bottom-feeding fish species but can have a slightly greater impact on water quality due to faster dissolution and accumulation at the bottom.
