Can I Feed My Marine Fish Brine Shrimp and Mysis Shrimp?

The trade-off is that live foods can occasionally introduce disease or parasites, especially foods sourced from marine environments. Freshwater-origin live foods carry far less disease risk, making them the safer choice for most hobbyists.

Brine Shrimp (Artemia): The Versatile Live Food

Brine shrimp are one of the most popular live foods for marine aquariums because they're available in two useful forms: newly hatched nauplii and adults.

Newly Hatched Brine Shrimp (Nauplii)

The nauplii are tiny enough to feed dwarf seahorses, pipefish, and other small fish, as well as filter-feeding invertebrates like feather-duster worms. You can hatch them at home in 24-48 hours from cysts (often called "brine shrimp eggs," though they're actually dormant embryos).

Adult Brine Shrimp

Adult brine shrimp are eagerly accepted by most fish species that eat live food. However, for most fish, they should be a supplement rather than the sole diet-they lack sufficient nutritional density on their own.

You can buy live adult brine shrimp from most aquarium retailers; they must be kept in clean saltwater in your refrigerator.

The Enrichment Step

The biggest drawback to brine shrimp is their poor baseline nutrition. To improve this, enrich them before feeding by allowing them to consume nutritious particles for 1-2 hours. Effective enrichment options include:

• Dried Spirulina (very effective; add about ⅛ teaspoon per small batch)
• Yeast (small amounts)

• Microalgae
• Egg yolk
• Commercial enrichment products like Selcon (1 mL per 5 ounces of shrimp)

When enriched, the brine shrimp will take on a greenish color, signaling they've absorbed the nutrients. Feed them to your fish at this point.

How to Hatch Brine Shrimp at Home

Hatching brine shrimp is straightforward and cost-effective if you need them regularly:

• Use a clean container-a 1-gallon glass jar or dedicated cone-shaped hatcher. Avoid any container that held detergents or chemicals.
• Prepare synthetic seawater at a specific gravity of 1.018-1.023 and pH of 8.0-8.8. Fill the container halfway to three-quarters full.
• Add cysts-typically 1-3 teaspoons, depending on the brand. These are sold at most pet stores.

• Aerate continuously with an air stone attached to a good air pump. Keep water moving but don't create heavy foam.
• Maintain temperature at 75-85°F (23.9-29.4°C) for the entire cycle. Warmer water speeds hatching (closer to 24 hours); cooler water takes up to 48 hours.
• Harvest the nauplii: After 24-48 hours, turn off the air stone and shine a light at the container's bottom. The newly hatched shrimp (a light orange mass) will congregate toward the light. Siphon them off carefully, avoiding the cysts.

• Store extras in a small, lightly covered container in the refrigerator for a few days.

Tip: Keep a continuous supply by cleaning the hatching container and starting a fresh batch as soon as you harvest.

Mysis Shrimp: The More Nutritious Option

Mysis shrimp are significantly more nutritious than brine shrimp and are the preferred choice for seahorses, pipefish, and other small, specialized feeders.

What Makes Mysis Better

Mysidopsis bahia, the most common species in aquarium trade, naturally occurs in Florida and Gulf of Mexico coastal waters. These tiny crustaceans-usually less than 10 mm long-have an excellent amino acid and fatty acid profile. Fish eagerly accept them, and they require no enrichment to provide good nutrition.

Availability

Unlike brine shrimp, mysis are available in multiple forms:

• Live cultured - available from some suppliers who specialize in tank cultures
• Frozen - the most readily available form in retail aquarium stores
• Marine vs. freshwater species - marine species are preferable, though the freshwater Mysis relicta has been used successfully for seahorses and pipefish

The frozen product is convenient and still highly nutritious, making it an easy alternative if you don't want to culture live food.

Culturing Mysis at Home

If you feed mysis regularly, some suppliers provide starter cultures and instructions for home breeding. A culture requires space, patience, and consistent maintenance, so it's best suited to serious hobbyists or those with frequent feeding needs.

Other Live Food Options

While brine shrimp and mysis are the most versatile, several other live foods suit specific fish:

Tubifex Worms

Readily available and eagerly eaten by butterflyfishes, batfish, and blennies, tubifex worms are nutritious but require careful handling:

• They must be washed thoroughly (15-20 minutes under slow cold water) before feeding, as they harbor debris and bacteria.
• Daily rinsing and water changes during storage are essential.
• They can burrow into substrate if not consumed immediately, fouling the water-start with small portions.
• They can be refrigerated for several days.

Earthworms

Excellent for larger, predatory fish like triggerfish, squirrelfish, hawkfish, blennies, and snappers. They have a strong nutritional profile and can be collected after rain, purchased from bait shops, or fed whole or chopped. Rinse them well before feeding to remove soil.

White Worms

Small white worms are a good supplement for small marine fish and can be cultured at home by patient hobbyists, though they're also available commercially. Like tubifex, they should be rinsed before feeding and only small portions offered to ensure consumption.

Small Live Fish

Certain predatory fish-particularly lionfish-require live fish to thrive in an aquarium. Acceptable options include freshwater baitfish (minnows, mollies) and small marine fish from bait shops.

Important note: Do not feed only goldfish to lionfish, as studies have documented severe liver damage from a goldfish-only diet. Offer a varied diet of different freshwater and marine species.

Building a Feeding Strategy

For most aquarists, a combination approach works best:

• For specialized feeders (seahorses, pipefish): Rely primarily on enriched brine shrimp nauplii or, better yet, live mysis.
• For general fish: Offer live foods as a supplement to high-quality flaked, pellet, or frozen foods. This provides variety and stimulates natural hunting behavior.
• For picky eaters: Start with live food to encourage feeding, then gradually transition to frozen foods if desired (though not all fish will accept this).

The key is matching the food size to your fish's mouth size and selecting foods that match each species' natural diet. A well-rounded feeding program keeps your marine fish healthy, engaged, and more likely to display natural behaviors in captivity.

Related Feeding Topics

For specific fish species, feeding requirements vary. Check our guides on clownfish food and feeding frequency, what fish eat crustaceans, and soft coral feeding in reef tanks for more species-specific advice. If you're setting up a quarantine tank for new arrivals, remember to establish a feeding routine early-see how to set up a quarantine tank for details.