Various types of foods are available for marine fish and invertebrates. A good diet will include the requirements of each species. For this discussion, I will talk mostly on brine shrimp and mysis shrimp.
Pros and cons of live foods for marine fish
The advantage of feeding live foods is that the animal is receiving the ideal undeteriorated natural food, unadulterated by preservatives. Certain species of fish and invertebrates will eat only live foods.
The disadvantage of some live foods is that they can be carriers of disease agents, This tends to be the case only with foods of marine origin rather than those of freshwater origin.
Live foods for saltwater fish
Several live foods are readily available, including brine shrimp (Artemia), Mysis shrimp, and tubifex worms. Other suitable live foods are white worms, earthworms, and small fish such as minnows. If you live near the ocean, you can also collect small live shrimp to feed marine aquarium fish and invertebrates.
Brine Shrimp (Artemia)
Brine shrimp, both in the newly hatched stage (nauplii) and adult form, are excellent foods for marine organisms. The nauplii are perfect food for dwarf sea horses, pipefishes, and Other Small fishes, as well as for invertebrates such as feather-duster worms that capture small food particles as they pass over their tentacles. The adult brine shrimp is an excellent food for virtually all species of fish that will accept only live foods. For most fish, however, brine shrimp should be considered a supplement rather than the sole dietary item.
Live adult brine shrimp can be obtained from most pet retailers. These shrimp must be maintained in clean saltwater and kept in the refrigerator. Nauplii can easily be hatched from eggs (brine shrimp cysts). This occurs within 24 to 48 hours, depending on the hatch conditions.
Since most brine shrimp are poor nutritionally, they should be enriched to increase their nutritional value. This is especially important when they are being used as the main portion of the diet, such as for sea horses, pipefish, and other species. Brine shrimp are filter feeders; therefore, they will eat small particles such as yeast, microalgae, egg yolk, dried Spirulina, and other materials.
Dried Spirulina is particularly good. A commercial product such as Selcon is also excellent for enriching brine shrimp. The formulation is composed of desirable fats and vitamins. The general directions for using Selcon call for adding a 1-mL portion of the material to a 5-ounce (142-g) portion of brine shrimp.
In addition, add approximately ⅛ teaspoon of dried Spirulina. Allow the brine shrimp to feed on this for two hours or until they begin to take on a green color. They can then be fed to sea horses or other fish.
Hatching Brine Shrimp
Live baby brine shrimp are excellent for feeding small fish and invertebrates. For certain fish such as dwarf sea horses, a supply of brine shrimp is essential. It is not difficult to hatch them at home using the following procedure.
- Obtain a hatching container such as a clean 1-gallon (3.8 L) glass jar or a specially designed clear cone-shaped brine shrimp hatching container. Make sure the containers are clean. Never use containers that have previously been used for other purposes, as residues of other chemicals or detergents can interfere with proper hatching of the brine shrimp.
- Fill the container approximately one-half to three-quarters full with freshly made synthetic seawater. The specific gravity should be within a range of 1.018 to 1.023. The pH should be within a range of 8.0 to 8.8. The temperature of the water should be maintained within 75° to 85°F (23.9° to 29.4°C) for the entire hatching procedure. At the higher end of the range, the brine shrimp will hatch faster, usually within 24 hours.
- Add a sufficient amount of brine shrimp cysts to the hatching container. Approximately 1 to 3 teaspoons of cysts will supply an ample amount of brine shrimp. The amount added will depend on the type of cysts purchased. Brine shrimp cysts, incorrectly called brine shrimp eggs, can be readily purchased at retail pet stores.
- Add an air stone that is attached to a good air pump and rapidly aerate the water to keep the cysts in suspension. The water should not bubble so rapidly that foam is formed on the water surface.
- The cysts should hatch within 24 to 48 hours. To remove the newly hatched shrimp, remove the air stone. Direct a light source toward the bottom of the container. Allow the brine shrimp to congregate. They will tend to concentrate at the bottom of the container near the light source. As they congregate, you will observe a light orange mass, which are the newly hatched shrimp.
- Carefully place a siphon into the container and siphon off the brine shrimp, taking pains not to remove too many cysts. The shrimp can then be fed to your fish or invertebrates. Store extra live brine shrimp in a small open container in your refrigerator.
- Clean out the container completely, wash the air stone, and repeat the instructions to hatch additional brine shrimp.
Check our previous post for continuous brine shrimp hatchery aquarium.
There are numerous species of these small shrimp occurring in both freshwater and marine environments. Also known as Opossum shrimp, the Mysis shrimp, Mysidopsis bahia, is a popular marine shrimp used to feed sea horses, pipefishes, and other small fish.
These small crustaceans, generally less than 10 mm in length, can be found in the coastal sea areas of Florida and the Gulf of Mexico. They are a much more nutritious food source with an excellent amino acid as well as a fatty acid profile.
They are eagerly accepted by aquarium fish. This species lends itself well to tank culture if a large number of these shrimp are needed on a regular basis. A number of companies have set up facilities for providing live tank-cultured Mysis shrimp to aquarists and public aquariums. They provide an initial stock of Mysis shrimp as well as instructions on how to culture them at home.
Mysis shrimp are available as a live as well as a frozen product. The frozen product is most readily available in retail aquarium stores and is produced by various aquarium food suppliers. The shrimp are excellent for feeding marine aquarium fish and invertebrates.
Marine species are preferable for feeding marine aquarium fish, although a freshwater species, Mysis relicta, has been used extensively to successfully feed sea horses and pipefishes. Mysis shrimp are the preferred choice for feeding sea horses and pipefishes.
These are also readily available for feeding marine fish. They are particularly relished by butterflyfishes, batfish, and blennies. These worms of freshwater origin have high nutritional value and are readily accepted by fish.
They can be maintained alive for several days or longer, depending on storage conditions. The disadvantage of these worms is that they must be consumed immediately before they burrow into the substrate, where they could foul the aquarium water. Start with a small portion of worms, adding worms only after the previous portion has been eaten.
Tubifex worms harbor large amounts of debris, organic materials, and potentially pathogenic bacteria. They must therefore be washed very well prior to feeding to marine fish or invertebrates. After purchasing the tubifex, place them in a small bowl in a sink with a slow flow of cold water for 15 to 20 minutes, or until the water remains clear. Store in a partially covered container in the refrigerator. Every day, pour off the cloudy water and replace it with new cold freshwater.
These are excellent food for marine fish and invertebrates and are especially relished by certain fishes such as triggerfish, squirrelfish, hawkfish, blennies, snappers, and other predatory fishes.
Earthworms have an excellent nutritional profile. They can be collected in virtually any rich soil or after a rainstorm when they tend to collect on the ground. Earthworms can also be purchased from bait stores. Earthworms can be fed whole or chopped into pieces just before feeding. Since earthworms ingest large amounts of soil, it is recommended that pieces of worms be rinsed well before feeding.
White Worms (Enchytraeus)
These small worms are a good food supplement for small marine fish. White worms are available commercially, but they are often bred at home by aquarium hobbyists. However, as with the culture of any live food, it requires time and patience for best results.
White worms must be rinsed well prior to feeding to marine fish. As with tubifex worms, only small numbers should be fed to ensure that the worms are consumed within a reasonable time. While white worms are excellent food, they should be considered only a supplement for marine fish.
To survive in an aquarium, certain fish and invertebrates must receive live prey. Among these are the various species of lionfish. Various types of fish can be fed, including live-bearers such as minnows, mollies, and others.
Feeding goldfish to lionfish is not recommended. It is well-known that severe damage to the liver can occur when feeding only goldfish to lionfish. If live fish must be offered, feed a variety of freshwater species and marine species. Bait shops are good sources of small baitfish.
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