Fish Feed Types: Floating vs Sinking Pellets for Aquaculture

Fish food pellets are not one product. A bag of floating pellets and a bag of sinking pellets solve different problems, and picking the wrong one wastes feed and money every single day you run the pond. This is the decision farmers ask us about most after they ask about aerators — so here is how to make it once and get it right.

Floating fish food: watch them eat, waste less

Floating fish food is extruded — cooked under pressure so trapped air keeps the pellet on the surface. That single trait is why most tilapia and catfish operations default to it: you stand at the pond edge and see exactly how fast the fish are eating. Slow feeding tells you something is wrong — low oxygen, disease, a temperature drop — before it shows up as a mortality count. Feed conversion is also easier to manage because uneaten pellets stay visible and you can cut the ration on the spot instead of guessing.

The tradeoff is cost. Extrusion uses more energy than pelleting, so floating fish food usually runs 10–20% more per bag than sinking pellets of the same protein spec. For species that naturally feed at the surface — tilapia, most catfish, koi — that premium pays for itself in visibility and lower waste.

Sinking fish food: for bottom feeders and dense stocking

Sinking fish food is compressed rather than extruded, so it holds together without trapped air and drops to the bottom. Shrimp, prawns and bottom-dwelling species like most catfish fry feed naturally where the pellet lands, not at the surface — sinking or slow sinking fish food matches that behavior. In high-density tanks it also spreads more evenly across the tank floor instead of clustering at one feeding point, which cuts competition and size variation at harvest.

The downside is you cannot watch the fish eat. Uneaten sinking pellets dissolve into the water column, driving up ammonia and clouding the water — this is why shrimp farms pair sinking feed with tighter water testing and conservative feeding tables rather than eyeballing consumption.

Choosing pellet size and protein

Pellet size should track fish mouth size, not tank size. Fry start on crumbles under 1mm, fingerlings move to 2–3mm pellets, and grow-out fish take 4–8mm depending on species. Feeding an undersized pellet to adult fish wastes feed through spillage and uneaten fines; an oversized pellet to juveniles simply goes unfed.

Protein follows the growth stage: fry and fingerling diets run 35–45% protein, grow-out diets settle to 28–32% for tilapia and 32–38% for carnivorous species like catfish and trout. Buying one generic commercial fish food for every stage is the single most common way farms overspend on feed while underfeeding fry.

Buying in bulk: price, storage, suppliers

Fish feed price per 50kg bag moves with protein content, pellet type and freight — floating pellets, higher protein and imported brands all push the number up. Bulk fish pellets bought by the tonne from local fish feed companies usually beat 50kg-bag pricing by 15–25%, but only if you have dry, pest-proof storage; feed that absorbs moisture molds fast and a mold-contaminated batch can cost you more than the bulk discount ever saved.

When vetting fish food suppliers, ask for the feed conversion ratio (FCR) at your target species and stage, not just the protein percentage on the label — two feeds at the same protein can perform very differently in the water. Pair the right pellet type with a properly sized automatic feeder and you cut labor and reduce the overfeeding that drives up ammonia in a biofloc or recirculating system.

For species-specific feed guides, see Tilapia Feed: Pellet Types, Nutrition & Feeding Schedule and Pond Fish Feed: Seasonal Feeding & How to Choose the Right Food. For the feed itself, see our fish and shrimp feed range.