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Benefits of Live Aquatic Food

Updated: Aug 30, 2022

Commercial fish foods in the form of flake, frozen or freeze dried can lose a significant portion of their nutrient contents in processing. These nutrients, in the form of protein, fats, vitamins and minerals are then often artificially added to ensure the nutritional needs of your fish are met.
Live foods have a high nutrient content that has not been altered by processing so it is natural and nutritious with nothing added and nothing taken away. High in protein, amino acids and fats it plays a key role in filling any nutritional gaps left when feeding your fish commercial food and it helps to keep your fish active. Live foods won't break down in the aquarium if not eaten quickly so will not affect the water quality and gives your fish a welcome change from dried or frozen.
Best of all, your fish will love live food. They will become more active and alert when you feed it and you will see the difference as they respond to feeding as they would in the wild. When used in the diet for breeding programmes live food will help bring your fish quickly up to breeding condition.
Our brine shrimp are raised in a controlled and sterile environment; which means it is clean and disease free. You can feed live food from Yorkshire Brine Shrimp knowing that you are giving your fish food as they would eat in the wild - live, natural and nutritious.

Brine Shrimp

Brine shrimp are a crustacean with stalked, compound eyes and a tapered body that has 11 pairs of legs. They can live in a remarkable range of salt water environments from those having water several times the salinity of seawater to water having only one tenth the marine salt concentration. They are found only in inland saltwater and not in the oceans - possibly because they more are susceptible to the many predators in the ocean.
When conditions are good, mature females release developing, free-swimming embryos into the water. But when temperatures drop and food is scarce the females release dormant cysts, often referred to as eggs. Inside the cysts, the development of embryos stops and they can remain dormant for several years. When conditions improve, the embryo resumes development, and the life cycle continues. At Yorkshire Brine Shrimp we take only the very best quality cysts from Great Salt Lake, Utah that have been harvested, dehydrated and sealed into a container with an inert gas that ensures the optimum storage conditions. We then prepare them and reintroduce them to a sterile and stable environment for hatching and raising.
Newly hatched brine shrimps are known as nauplii and they survive initially on the nutrients available to them from the egg sac, which they absorb. A nauplius is essentially a swimming head with a small and relatively
undeveloped trunk that looks nothing like an adult brine shrimp. Nauplii are small enough to feed to fry, and some hobbyist's suggest that they are more nutritious than adult brine shrimp. Research has shown the nutritional value of nauplii varies considerably depending on where the eggs originate, time elapsed since hatching, water quality and several other factors including what they feed on after egg absorption. The egg sac is absorbed in a matter of hours after hatching. Brine shrimp reach maturity in around 10 days and in that time they have increased in length by a factor of 20, and in biomass by a factor of 500.

Mature brine shrimp grow to around 8-10mm with the male having a more pronounced, pincer like head. When sexually mature the ovaries can be seen on the female as a pair of small black dots in the middle of the body. Brine shrimp have a a relatively thin exoskeleton so they can be fully digested by predators. Much of the biomass is in the form of proteins and lipids - as much as 60% protein and 20% lipids dry matter content. Live brine shrimp do not cause water deterioration like uneaten frozen or freeze dried food can, and studies have shown that fish fed on live brine shrimp grow faster and maintain better condition than those fed on frozen and freeze-dried.​
Live brine shrimp can be fed to marine and freshwater fish and will live for several hours when introduced to a freshwater aquarium, giving plenty of time for your fish to find and devour them.


Hatch in the bag

Hatch in the bag contains thousands of tiny hydrated and decapsulated brine shrimp cysts (eggs). The decapsulation process removes the outer shell leaving only the embryo and egg sac contained within a thin membrane. Decapsulation is carried out because the shell can become stuck in the digestive tract of small fish and to improve the hatch rate of the cysts.
Hatch in the bag can be fed to fish of any size, marine or freshwater but is particularly suited as a feed for fry due to it's small size of around 200 microns (0.2mm).



Daphnia are small (0.5-3mm), almost transparent, freshwater crustaceans with two feather like antennae and only a single compound eye. Their bodies are enclosed by a carapace and within the carapace they have leaf-like limbs they move to produce a current of water that circulates oxygen and nutrients to their mouth and gills. They swim by using downward strokes of their large antennae and move in a jerky motion that resembles a flea, giving them their common name of water fleas.
The eggs hatch in the brood chamber within the carapace of the female daphnia and the juveniles are released in approximately two days when the female molts - they go on to reach maturity in around 6 to 10 days.
The nutritional value of daphnia varies depending on the water it was living in and the food that was available to it. Studies have found that dry matter content is around 40% protein with 5% fat and fibre and that it provides all the nutritional requirements of omnivorous fish like carp.
Daphnia is not suitable for feeding to marine fish as they die quickly in salt water and may break down causing water deterioration. Feed to freshwater fish.



Bloodworm are not actually a worm but the larvae stage of a midge that is similar in size and shape to a mosquito, however it does not bite or carry disease. Growing to around 25mm in length, it normally takes around two weeks from hatching to pupating. However, this is temperature dependent and can be extended significantly when kept refrigerated.
Bloodworms live in the top few centimetres of mud in freshwater ponds and breathe by leaving their tail out of the mud and waving it in the water, feeding on microscopic particles. They are a natural and nutritious food for freshwater fish and you will find even the pickiest of feeders will relish them. Similar dry matter content to other live foods with around 60% protein and 15% lipids but also containing iron in the haemoglobin type substance that gives them their red colour.


Tubifex Worm

Tubifex worms live in the mud and silt at the bottom of lakes and rivers and, like earthworms, they have little bristles on their sides to provide traction for burrowing into the sediment. They keep their tails clear of the sediment to allow for absorption of oxygen from the water.
Tubifex have a reputation of being dirty and possibly carrying disease but provided they are well cleaned there is little evidence to suggest they cause problems in aquariums. Tubifex worm supplied by Yorkshire Brine Shrimp are cleaned and flushed under running water for several days before being sold.
Higher in fat content than bloodworm, they can be used to promote growth in fish but care should be taken to ensure they are only used as part of a balanced diet.


River Shrimp

River shrimp are sometimes known as feeder shrimp and are found in estuary's and brackish water rivers. Great for larger predatory fish like cichlids, large wild betta and puffer fish. High in protein, your fish will enjoy chasing them as well as benefit from the high nutrient content. Feeding live river shrimp is a great way to get any of the larger freshwater or marine fish to feed.


Marine Copepods

In our oceans copepods constitute the largest part of zooplankton and are a natural food for many marine fish and even whales so have great importance in the food chain. It is estimated that there are around 13,000 species of copepods and they can be found in salt and freshwater and even in damp areas and moss.
This natural and nutritious food is a firm favourite of virtually all marine aquarium fish. Copepods can also scavenge any food that is left and eat algae so have additional benefits and are often kept in the aquarium or refugium as part of the ecosystem. Around 0.5 - 1.0 mm in size they can be fed to fry and small fish when brine shrimp are considered too large.
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