The one animal on this site nobody keeps
Every other page here is a care record: an animal, its water, and how to keep it alive. This one is not, and saying so is the first useful thing it can do. Brine shrimp are a saltwater crustacean hatched in a jar and fed to freshwater fish within a day or two, and almost nobody keeps them for their own sake.
That is why this is a guide rather than a record. A record on this site carries a minimum tank, a pH and a list of tank mates, and every one of those fields would be a category error here. What brine shrimp have instead is a recipe, a clock and a size, and those three things are what the rest of this page is about.
The name is shared, more than usual. The genus is Artemia. Wikipedia profiles Artemia franciscana Kellogg, 1906, native to heavily hypersaline environments of the Americas and the Caribbean and now widely introduced through the tropics and temperate zones. AlgaeBarn writes about Artemia salina. Our sources do not agree on which species is in the can, and none of them says.
The search term is shared too. The top results for it include a university page about the Great Salt Lake food web, several patents for harvesting machines, and a recipe for brining shrimp for dinner. None of those is this page.
Why this guide was written now
- The gap
- At 22,000 searches a month it is the largest term left in our keyword map, and seven of our fourteen records already have sources that name brine shrimp as a food. Nothing on the site explained what it is.
- Why it is not a record
- A saltwater food organism in the record set would appear in every freshwater stocking grid and count as a species this site keeps. It is a guide, filed under breeding, and it shows on the shrimp silo as a guide.
- What it does not answer
- Two things. No source we read gives a salinity in parts per thousand, and none treats keeping brine shrimp as a display animal as something people do.
Four recipes, and one brand publishes two of them
Every source that hatches brine shrimp gives a recipe, and no two are the same. The table is what each one actually states, in the units it used. Nobody converts their salt to a salinity, which is why the guide carries no salinity figure.
| Source | Water | Salt | Eggs | Temperature | Time |
|---|---|---|---|---|---|
| Aquarium Co-Op, article | 1.75 L tap | 2 tbsp marine or aquarium salt | 1 tsp to 1 tbsp | 74 to 82 °F | 18 to 36 h |
| Aquarium Co-Op, FAQ | About 2 L | 2 tbsp, aquarium salt if hard water, marine if soft | Up to 1 tbsp | 74 to 82 °F | 24 h |
| Tropical Fish Hobbyist | 1.4 L tap, 125 ppm GH | 2 tbsp salt plus 1 tsp Epsom, giving a specific gravity of about 1.019 | 1.5 tsp, 4.2 g | 80 to 84 °F | 18 to 24 h |
| Tropical Fish Hobbyist | Same hatcher | Same | Same | Below 78 °F | Up to 36 h |
- One brand, two pages, two answers. Aquarium Co-Op's article says 1.75 liters and 18 to 36 hours; its own FAQ says approximately 2 liters and wait 24 hours. Neither is wrong and the difference matters if you are measuring. This is the third time on this site that one source has published two figures for the same thing, after Aqueon on angelfish tank size and Aquarium Co-Op on cherry shrimp pH.
- The temperature disagreement is not one. Co-Op gives 74 to 82 °F and a range of 18 to 36 hours. Tropical Fish Hobbyist gives 80 to 84 °F and 18 to 24 hours, and then explains the other source's range: below 78 °F it will take up to 36 hours for most of your shrimp to hatch. The two together are a curve, not a conflict.
- There is a ceiling and only one source states it. Over about 86 °F, Tropical Fish Hobbyist says, the nauplii will suffocate quickly. Warmer is faster right up to the point where it kills them.
- Chlorine is not the enemy here, and chloramine is a different question. Aquarium Co-Op's article states that if your water contains chlorine you do not need a dechlorinator, because the chlorine helps dissolve the egg casings and gasses off before the shrimp hatch. Its FAQ says to use 1 to 2 drops of dechlorinator if your tap water has chloramine. Those look like a contradiction and are not: chlorine gasses off and chloramine does not. Tropical Fish Hobbyist uses chloramine containing tap water on purpose and hatches in it anyway. All of that is the opposite of the advice every other page on this site gives about tap water.
- The one figure both technical sources agree on is not in the table. pH. Tropical Fish Hobbyist says that if the water is not pH 8 or higher after the shrimp hatch, you need to add buffer, and its own tap water is 125 ppm GH with 3 degrees of KH.
450 microns, and why that number decides everything
The size at hatch
Aquarium Co-Op publishes the figure that makes this food useful: baby brine shrimp hatch out at 450 microns in size. That is 0.45 mm, and it is the whole reason the hobby bothers with a jar and an air pump instead of buying a jar of flakes.
Set it against the adult. AlgaeBarn says they grow to around 8 mm and take about a week to mature. The University of Utah puts the maximum at just over 1 cm, and adds that at that size they are the largest animals that live in the Great Salt Lake. So the animal spans roughly twenty times its hatch length, and the two ends of that range are sold as two different products.
A fry that can eat a 450 micron nauplius cannot eat an 8 mm adult, and a fish that will eat the adult has no use for the nauplius. Every mention of brine shrimp across our records is one or the other, and the records that say baby brine shrimp mean it.
What our own records say
Seven of our fourteen records have sources that name brine shrimp, and they split exactly along that line. Our ember tetra record lists baby brine shrimp among the small foods Aquarium Co-Op names for a fish that is 15 to 20 mm long. Our pea puffer record names frozen brine shrimp for a 25 mm predator.
At the other end, our oscar record carries the only refusal: Tropical Fish Hobbyist rules out small frozen foods such as brine shrimp and bloodworms for anything but the smallest juveniles. A 12 inch fish gets nothing from a 0.45 mm crustacean.
In between, our betta, guppy, angelfish and kuhli loach records all name brine shrimp as an occasional or supplementary food rather than a staple. Not one of those sources says which size.
The hatchery itself, which is a bottle or a valve
Two kinds of vessel
A brine shrimp hatchery is either something you bought or something that used to hold soda, and our two technical sources use one of each. Tropical Fish Hobbyist works in a 2 liter soda bottle hatcher and fills it with 1.4 liters. Aquarium Co-Op describes a purpose built hatchery holding about 2 liters, with an output spout and a valve at the bottom.
What both have in common is the air line, and station 06 is where that matters: if the eggs come to rest they will not hatch. The air is not aeration in the tank sense, it is what keeps a few thousand cysts in suspension for a day.
Neither source recommends a heater in the water as the first option. Aquarium Co-Op lists three ways to reach 74 to 82 °F and puts the heater last: heat the whole room, shine a small lamp with an incandescent or halogen bulb, or place a small heater inside the water. Tropical Fish Hobbyist simply hatches at 80 to 84 °F with an ambient light source nearby.
Harvesting, which is where the valve earns its keep
Aquarium Co-Op's FAQ gives the method in two sentences and it depends on the animal rather than on equipment: turn off the air pump and shine a light near the output spout at the bottom to attract brine shrimp for collecting, then open the output valve to collect the shrimp.
That works because the shells float and the nauplii swim toward light. A bottle without a valve does the same job with a length of airline used as a siphon, which is the difference between the bought hatchery and the DIY one: not the hatch, the harvest.
On rinsing, the same source is relaxed about it: you can rinse the brine shrimp, or feed with the salt water if your tank needs minerals for live plants or hard water fish. A teaspoon of hatchery water in a tank is not the salinity problem it sounds like, and no source we read gives a figure for how much salt that adds.
The nutrition clock, which is the part nobody mentions
This is the most useful thing we found on the subject and it comes from one source. Tropical Fish Hobbyist is the only page we read that quantifies what happens to a newly hatched brine shrimp while it waits to be eaten.
- They do not feed at first. For about the first 12 hours after hatching the nauplii do not feed at all, because they are still living on a yolk sac.
- Then the value starts falling. If they are not fed by the end of the second instar, at approximately 24 hours post hatch, the source reports they may lose up to a fifth of their body weight and more than a quarter of their nutritional value.
- The fat is the point. Body fat starts at up to 32 percent of total body weight and can drop considerably, by as much as 39 percent. Aquarium Co-Op's reason for using them at all is the same figure from the other side: a nutrient dense food that maximizes the survival rate of fry and significantly speeds up their growth.
- Which is why the storage advice is short. Aquarium Co-Op says to refrigerate the harvested liquid and use them within the next two or three days. Cold slows the clock; it does not stop it.
- And why they are fed live. Aquarium Co-Op states that baby brine shrimp can only survive in freshwater for a few hours. A nauplius put in a fry tank is either eaten soon or it is not food any more.
Put the three figures together and the whole practice makes sense. You hatch on a schedule, harvest at 18 to 24 hours, feed within the day, and hatch again. Aquarium Co-Op calls live baby brine shrimp the number one recommended fry food used by veteran fish breeders and major fish farms, and the reason is a 24 hour window rather than the animal itself.
Our breeding topic holds what our sources say about the fish that produce fry in the first place. This page is what you do the week after.
Why a hatch fails, from the source that tested it
Brine shrimp not hatching is one of the most searched problems in this cluster, and one source answers it with reasons rather than reassurance.
- The pH was too low. Tropical Fish Hobbyist: if it is still not pH 8 or higher after they hatch, you need to add some buffer to your water. It is the only figure in the whole recipe that is about the water rather than the salt.
- The eggs settled. If the eggs come to rest they will not hatch, and brine shrimp need oxygen to live. That is what the air line is for, and it is not optional.
- The water was reused. The less than two cents per hatch you save will more than be made up for by the decreased hatch, because the reused water is filthy with biological material.
- The eggs were stored badly. Whatever you do, do not bring the jar back up to room temperature every time you want to measure out some eggs. Aquarium Co-Op says the same thing in the positive: keep a small working portion accessible and store the rest in the fridge or freezer, away from oxygen, humidity and heat.
- The eggs were poor to begin with. Buy a one pound sealed can of eggs and buy at least an 80 percent hatch rate. It is the only quality figure any of our sources publishes, and it means a fifth of a good can is expected not to hatch.
Adults, and whether you can raise them
What the animal does if it lives
AlgaeBarn gives the life history our other sources skip: they grow to around 8 mm, take about a week to mature depending on conditions, and after they mature they can live for several months and produce as much as 75 eggs every day.
Wikipedia's figures for Artemia franciscana are larger and more precise. Females produce up to 250 embryos per brood and up to 20 broods in a lifetime, maturity is reached in 15 molts all occurring in less than 20 days, and reproduction is optimal at 24 °C with reproduction still possible at 32.
It also names the two strategies, which is the detail that explains the can of eggs on the shelf: oviparity, laying eggs that develop and hatch outside the body, or ovoviviparity, where they develop and hatch inside the mother. The dried cysts sold to the hobby are the first of those.
How to raise brine shrimp is a different job
Two of our sources are clear that this is not something that happens by itself. AlgaeBarn states that brine shrimp will most likely not reproduce in your refugium, unlike other small crustaceans, and advises against putting them in a sump for that reason.
Nothing we read treats a brine shrimp as an animal you keep to look at. That is worth stating plainly on a site whose other fourteen pages are about animals people keep, and it is why this guide has no minimum tank, no tank mates and no temperament.
What our sources do describe is growing them on to feed larger fish, which needs a food supply the nauplii do not: they are passive filter feeders, and the University of Utah names what they filter in the wild, cyanobacteria, the microscopic algae Dunaliella veridis, diatoms and detritus.
Where the can comes from, and it is one lake
This is the part of the subject no aquarium page carries, and it changes how the jar on the shelf reads. Our two non aquarium sources describe an industry.
- The University of Utah. At a maximum length of just over 1 cm, brine shrimp are the largest animals that live in the Great Salt Lake, each year millions of birds fatten up on them as they prepare nests or migrate, and the brine shrimp fishing industry brings in 70 to 100 million dollars annually.
- Wikipedia. Artemia franciscana has been introduced worldwide, in some places deliberately for economic reasons, and Brazil harvests 20 tonnes of cysts annually.
- What that means for a hobbyist. The teaspoon of eggs in a hatcher is a harvested wild product from a hypersaline lake, sold by the sealed can with a stated hatch rate. That is a supply chain rather than a care instruction, and it is the reason the storage advice in station 06 is as specific as it is.
- And a note this site has made before. Our ghost shrimp record is about another animal sold as food, where Wikipedia's own label for the species is feeder shrimp. The two pages are the same subject from two directions: what the hobby feeds, and what the hobby feeds it to.
What this guide will not answer
- What brine shrimp salinity to aim for. Not in parts per thousand, because no source we read gives one. Two tablespoons of salt in 1.4 to 2 liters is what they publish, and Tropical Fish Hobbyist is the only one to convert it at all, to a specific gravity of about 1.019.
- Which species is in your can. Wikipedia profiles Artemia franciscana and AlgaeBarn writes about Artemia salina. No source we read says which one the hobby sells, and the can rarely says either.
- Whether brine shrimp can be a pet. It is a search people make. Nothing we read describes keeping them for their own sake, so this guide describes hatching and feeding and stops there.
- How much to feed a given fish. Our records name brine shrimp for seven species and not one of their sources gives a quantity. The betta tank mates guide is where this site sets out how it handles a figure nobody publishes.
Brine shrimp questions, answered from the sources
How do you hatch brine shrimp?
Salt water, air, warmth and a day. Aquarium Co-Op's recipe is 1.75 liters of room temperature tap water, 2 tablespoons of marine or aquarium salt, and 1 teaspoon up to a maximum of 1 tablespoon of eggs, heated to 74 to 82 °F, with the shrimp collected after 18 to 36 hours.
Tropical Fish Hobbyist runs a tighter version in a 2 liter bottle: 1.4 liters of warm tap water, 2 tablespoons of salt plus a teaspoon of Epsom salt for a specific gravity of about 1.019, and about 1.5 teaspoons of eggs at 80 to 84 °F, with almost everything that is going to hatch hatched in 18 to 24 hours. Station 02 puts every recipe side by side.
Why are my brine shrimp not hatching?
Tropical Fish Hobbyist gives five reasons and station 06 lists them all. The two most mechanical are pH and movement: if the water is not pH 8 or higher you need to add buffer, and if the eggs come to rest they will not hatch, because brine shrimp need oxygen to live.
The other three are about the eggs rather than the water: reused hatching water is filthy with biological material and cuts the hatch, eggs warmed up to room temperature repeatedly degrade, and a can should be bought sealed with at least an 80 percent stated hatch rate.
How big are baby brine shrimp?
450 microns at hatch, which is 0.45 mm, from Aquarium Co-Op. It is the figure that decides which fry can eat them.
An adult is roughly twenty times that. AlgaeBarn says they grow to around 8 mm, and the University of Utah gives a maximum of just over 1 cm, noting that at that size they are the largest animals living in the Great Salt Lake.
Do brine shrimp need salt water?
Yes, to hatch and to live. Every recipe our sources publish is a salt water recipe, and Wikipedia describes a genus native to heavily hypersaline environments.
The corollary is the figure that governs feeding: Aquarium Co-Op states that baby brine shrimp can only survive in freshwater for a few hours. That is why they are fed live and in small amounts rather than dosed into a tank.
How long do brine shrimp stay nutritious after hatching?
About a day, and Tropical Fish Hobbyist is the only source we found that quantifies it. The nauplii do not feed for about the first 12 hours because they are living on a yolk sac. If they are not fed by the end of the second instar, at approximately 24 hours post hatch, they may lose up to a fifth of their body weight and more than a quarter of their nutritional value.
Body fat starts at up to 32 percent of total body weight and can drop by as much as 39 percent. Aquarium Co-Op adds the practical version: refrigerate the harvested liquid and use them within two or three days.
How long do brine shrimp live?
Several months once they mature, according to AlgaeBarn, which also says they take about a week to mature depending on conditions. Wikipedia is more precise about the same process: maturity is reached in 15 molts, all occurring in less than 20 days.
Neither figure is the one that matters in a fry room, where the animal is eaten within a day of hatching.
What do brine shrimp eat?
Whatever is suspended in the water. The University of Utah describes passive filter feeders that collect whatever is in the water and sweep it into their mouths, and names cyanobacteria, the microscopic algae Dunaliella veridis, diatoms and detritus.
For the first 12 hours after hatching they eat nothing at all, which is the yolk sac in station 05. If you are growing them on to adult size, that filter feeding is the job you are taking on.
Can you keep brine shrimp as pets?
Nothing we read treats it as something people do. Every one of our six sources describes hatching them as food, and AlgaeBarn goes as far as advising against putting them in a refugium because they will most likely not reproduce there.
This is the reason this page is a guide rather than a care record. A record here carries a minimum tank, a pH and a list of tank mates, and for this animal all three would be a category error.
What fish eat brine shrimp?
On this site, seven of fourteen records have sources that name it. Our ember tetra record lists baby brine shrimp for a 15 to 20 mm fish, our pea puffer record names frozen brine shrimp, and our betta, guppy, angelfish and kuhli loach records name it as an occasional food.
One record refuses it. Our oscar record carries Tropical Fish Hobbyist ruling out small frozen foods such as brine shrimp for anything but the smallest juveniles, which is the size argument from the other end.
Frozen, freeze dried or live?
Our sources only compare them indirectly, and the comparison is the nutrition clock. Aquarium Co-Op calls live baby brine shrimp the number one recommended fry food used by veteran fish breeders and major fish farms, and the figures in station 05 are the reason: the food value is highest at hatch and falls measurably within a day.
Frozen brine shrimp appear on our records as an adult sized food for adult fish, at the pea puffer and the oscar. No source we read publishes a nutritional comparison between the forms, so this guide does not rank them.
Where do brine shrimp eggs come from?
Mostly from one lake, and the figure is startling for a fry food. The University of Utah states that the brine shrimp fishing industry on the Great Salt Lake brings in 70 to 100 million dollars annually, and that millions of birds fatten up on the same animal each year.
Wikipedia adds that Artemia franciscana has been introduced worldwide, sometimes deliberately for economic reasons, and that Brazil harvests 20 tonnes of cysts annually.
Why is this a guide and not a record?
Because a record on this site carries a minimum tank, a temperature band, a pH, a hardness, a group size and a list of tank mates, and this animal has none of those in any sense a keeper could use. It is a saltwater crustacean hatched in a jar and fed to freshwater fish inside a day.
Putting it in the record set would also corrupt every count on the site: it would appear in the freshwater stocking grids, in the layer filters and in the tank mate matrix as though it were something you keep. So it is filed under breeding, listed as a guide on the shrimp silo, and the method page explains the distinction the site draws.