Best Selenium-Rich Foods for Freshwater Fishs

Ranked by selenium content among foods safe for freshwater fishs in the Creature Feast catalog.

Brine shrimp per 100g freeze-dried: ~50µg selenium Brine shrimp accumulate selenium from their aquatic environment, making them a reliable dietary source for freshwater fish. Selenium is a critical component of glutathione peroxidase, the antioxidant enzyme that protects fish cells from oxidative damage — especially important in the oxygen-saturated environment of a well-filtered aquarium.

Bloodworms per 100g freeze-dried: ~35µg selenium Bloodworms contain selenium from the sediments they inhabit, providing selenomethionine and selenocysteine in forms that fish incorporate directly into antioxidant enzymes. This selenium protects the delicate gill epithelium from oxidative stress.

Mysis shrimp per 100g frozen: ~30µg selenium Mysis shrimp provide selenium accumulated through the marine food chain. The selenium content supports thyroid hormone metabolism in fish, which regulates growth rate, metabolic activity, and reproductive cycling.

Spirulina flakes per 100g: ~7µg selenium Spirulina flakes contain selenium absorbed from their growth medium. The selenium in spirulina supports the selenoprotein enzymes that protect fish from the elevated oxidative stress present in aquarium environments with artificial lighting and high oxygen levels.