Live Foods for Aquarium Fish

An overview of common live foods, including brine shrimp, daphnia, bloodworms, and blackworms, with their nutritional benefits and the risks to manage.

Why use live foods

Live foods are close to what fish eat in nature and provide hunting enrichment that encourages underweight or growing fish to eat. They are also among the fastest ways to condition adult fish for spawning. Their main drawback is the potential to introduce disease or parasites, which makes sourcing and handling important.

Brine shrimp (Artemia)

Brine shrimp belong to the genus Artemia, with Artemia franciscana and Artemia salina commonly used in aquaculture. The newly hatched nauplii are the most widely used live food item for larval fish and crustaceans. Cysts hatch within a few hours to a day in salt water; in aquariums, hatching typically takes 18 to 36 hours at 74 to 82 degrees Fahrenheit (23 to 28 degrees Celsius). Newly hatched nauplii carry a nutrient-rich yolk reserve of fats and proteins and do not feed during their first stage.

Daphnia

Daphnia are planktonic crustaceans (cladocerans) commonly called water fleas, measuring about 0.2 to 6.0 mm in length. Common species include Daphnia pulex and Daphnia magna. They are filter feeders that consume unicellular algae, detritus, protists, and bacteria, and are a popular live food in freshwater and marine fishkeeping. They are sensitive to chlorine and prefer cooler water.

Bloodworms

Bloodworms are the larvae of chironomid midges. They are commonly offered frozen or live and help round out the diet of many species. Bloodworms are easy to overfeed, which can result in bloated fish, so portions should be controlled. Handling bloodworms can rarely trigger allergic reactions in some people.

Blackworms

California blackworms are commercially farmed and are valued for bottom-dwelling fish, particularly when conditioning corydoras catfish. Because they foul quickly, they require daily rinsing in cold, dechlorinated water held at about 40 to 55 degrees Fahrenheit.

Risks to manage

Worm-based foods can carry parasites: tubifex worms may carry Capillaria, and fish can acquire Camallanus by eating infested copepods sometimes sold as live food. Feeder fish carry a higher disease risk and are rarely quarantined. Some prey, such as goldfish and minnows, contain thiaminase, which can cause vitamin B1 deficiency if fed exclusively. Maintaining dietary variety reduces these risks.