When we decided to remove grain from Koi Fuel, that was not a marketing decision. It was a formulation decision. There is a major difference between the two.
Why Most Koi Feeds Rely on Wheat
Most commercial koi feeds rely heavily on wheat flour. Wheat is inexpensive, easy to source, and extremely cooperative during extrusion. It binds well and helps manufacturers produce uniform pellets with less technical difficulty. That is why it is used so widely.
But wheat is still grain. And koi do not require grain.
Wheat is primarily used in fish food as a binder and carbohydrate source. It helps pellets hold together and provides energy. However, it also contributes fiber and plant protein that does not offer the same biological value as marine protein. When wheat inclusion levels are high, the total carbohydrate and fiber load increases — and that has consequences inside a closed pond system.
The Hidden Cost: More Fiber, More Waste
Higher fiber means more indigestible material passing through the fish. That translates to bulkier feces and greater solid waste production. In practical pond terms, that means more organic load settling in the system, more mechanical filtration demand, and more breakdown of waste into dissolved organics. Over time, that contributes to murkier water, increased biofilter stress, and overall higher maintenance.
Koi can digest properly processed starch — that is not the issue. The issue is unnecessary grain fiber in a system where water clarity and biological stability matter.
Why Starch Is Still Necessary
When you manufacture extruded feed, starch is required. Under heat and pressure, starch gelatinizes and creates structure within the pellet. Without starch, pellets crumble, expansion becomes inconsistent, and water stability suffers. Removing starch entirely is not realistic if you want a high-quality, durable pellet. The real question becomes which starch source provides structure without compromising the nutritional integrity of the diet or increasing unnecessary waste output.
Why Potato Starch
Potato starch was chosen because it performs the mechanical job without bringing along unwanted extras. It is grain-free. It is very low in fiber. It gelatinizes efficiently during extrusion. It does not introduce gluten proteins. It does not dilute the marine protein profile. It binds the pellet cleanly and predictably. That is its role. Nothing more.
Digestibility is critical in koi nutrition. When starch is properly gelatinized, koi utilize it efficiently as an energy source. But excessive grain-based carbohydrate and fiber increase metabolic waste, contribute to dissolved organic buildup, and place additional demand on the biofilter. By lowering total fiber and removing wheat, we reduce unnecessary solid waste production and help maintain cleaner water.
Koi are opportunistic omnivores. They graze and nibble naturally. But optimal growth performance is driven by digestible marine protein and appropriate lipid levels, not grain inclusion. Marine protein should dominate the formula. Carbohydrate should support pellet formation and energy balance, not drive the feed.
That principle guided this formulation. Koi Fuel was designed around marine protein dominance, controlled fat for performance, minimal fiber, and zero grain inclusion. Potato starch exists strictly to ensure structural integrity during extrusion while keeping waste production and water impact lower than traditional wheat-heavy feeds.
If I put something in a formula, there is a reason for it. Potato starch is there for one reason: to hold together a pellet built on marine nutrition, not grain filler.
Feed a grain-free, marine-protein diet. Explore the full Koi Fuel range and see how much to feed your koi by body weight.
Jason Michael — Founder, Krazy Koi Meds. A 30-year aquaculture professional with experience in commercial koi farming and fish health management.
