Insect larvae meal in fish food: a genuine sustainable alternative?
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
More and more flakes and pellets now list "insect larvae meal" or "Hermetia illucens" among their ingredients, marketed as a sustainable alternative to fish meal. A study measured what this swap actually changes for the most commonly fed aquarium fish in the world, the goldfish. Our other feeding guides are gathered in the feeding your fish section.
Why replace fish meal at all
Traditional fish meal is made from wild-caught fish harvested specifically for aquaculture and animal feed, an increasingly costly and environmentally debated resource. Black soldier fly larvae (Hermetia illucens), raised on organic waste, then dried and ground, have become one of the most studied alternatives in recent years, both in food-fish farming and in ornamental aquarium keeping.
What the goldfish study measured
Khieokhajonkhet, Uanlam, Ruttarattanamongkol, Aeksiri, Tatsapong and Kaneko published a study in Aquaculture in 2022, replacing an increasing share of fish meal with black soldier fly larvae meal in goldfish diets, tracking growth, blood biochemistry, liver histology and coloration. Up to a replacement rate of 145 to 210 grams per kilogram of feed, growth, feed utilization and blood parameters improved compared to fish fed a standard fish-meal diet.
The trade-off that shows up at the highest rates
The picture gets more complicated at the highest replacement rates tested: total carotenoid content dropped in the fins, skin and blood serum, redness in the abdominal area declined, and mild liver cell vacuolization appeared under histology. In other words, insect meal is not worse for growth — it is actually better up to a certain point — but it supplies fewer of the pigments that give goldfish their bright colour, lacking the same carotenoids found in fish meal or marine prey. Our guide on colour-boosting food for goldfish covers how a carotenoid supplement can make up for that gap, whatever protein source is used.
What this means for picking a food
A food containing insect meal as a secondary ingredient, at a moderate rate, has no obvious reason to hurt fish health or colour — the environmental benefits stand with no visible trade-off. It is mainly for fish where colour is a buying criterion (fancy goldfish, koi) that it is worth checking the label to confirm a food that is mostly insect-based is topped up with a carotenoid source, as our guide on fish food supplements explains.
Frequently asked questions
Is insect meal bad for fish health?
No: in this study it improved growth and blood parameters up to a high replacement rate; only mild liver changes appeared at the maximum rate tested, well beyond what most commercial foods actually use.
Should insect-based foods be avoided for a brightly coloured fancy goldfish?
Not necessarily: just check that the ingredient list also includes a carotenoid source (spirulina, shrimp, astaxanthin) to make up for insect meal's lower natural pigment content.
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.