Frozen mysis shrimp are a high-protein, meaty food that most aquarium fish love, from bettas and cichlids to marine fish and seahorses. To feed them, thaw a small cube in a cup of tank water, drain or rinse it, and offer only what your fish can finish in a couple of minutes. Keep the unused portion frozen and never refreeze thawed mysis.
What are mysis shrimp?
Mysis, sometimes called opossum shrimp, are small crustaceans found in coastal waters and some lakes. They are not true shrimp, but they are a natural food for many fish and are widely sold frozen or freeze-dried. They are bigger than baby brine shrimp, rich in protein and fat, and a good source of nutrients like omega fatty acids.
How to feed frozen mysis shrimp
- Break off one cube or a small piece. Start with less than you think you need.
- Thaw it in a small cup of tank water for a few minutes. Do not use hot water or a microwave.
- Pour the thawed mysis through a fine net or turkey baster to drain off the juices, which can foul the water.
- Drop or squirt the shrimp into the tank near your fish. Use a target feeder or tongs for shy species.
- Remove any food that is not eaten after about five minutes.
How often to feed
Most freshwater fish do well with frozen mysis a few times a week as a supplement to their regular pellets or flakes. Marine fish and seahorses are often fed mysis once or twice a day, in small portions. Adjust to the size of your fish and tank, and skip a feeding if the fish look full or food is left over.
Which fish eat mysis?
- Bettas: A great protein treat, though bettas should not be overfed. See our guides on how much brine shrimp to feed a betta and betta treats.
- African cichlids: Carnivorous and omnivorous species enjoy mysis in moderation. See best frozen food for African cichlids.
- Marine fish and seahorses: Frozen mysis is a staple for many picky eaters. Seahorses can be trained to take mysis from a feeding station placed in a calm part of the tank.
- Goldfish: Occasional only. Goldfish need mainly plant-based foods.
Storing frozen mysis
Keep frozen mysis at 0 degrees Fahrenheit or colder in a freezer. Once thawed, use the portion that day and throw away the rest. Check the package for a best-by date, and discard cubes that are freezer-burned or have an off smell.
Common mistakes
- Feeding the thawing liquid, which clouds the water and can feed algae.
- Overfeeding rich foods like mysis, which can cause bloat or constipation in some fish.
- Skipping staple foods. Mysis should be a part of a varied diet, not the entire diet.
Bottom Line
Frozen mysis shrimp are a nutritious treat for most aquarium fish when thawed, drained and fed in small amounts. Use them a few times a week for freshwater fish, keep leftovers frozen and remove uneaten food from the tank.
