What you need to know about hatching baby brine shrimp

152fe684-51b8-456a-8370-ea74bf37e708

Editor's Picks
Features Post
The brightest pupils
04 October 2021
Features Post
Dealing with egg ‘fungus’
04 October 2021
Features Post
Rathbun’s tetra in the wild
13 September 2021
Fishkeeping News Post
Report: 2021 BKKS National Koi Show results
13 September 2021
Features Post
The World's forgotten fishes
16 August 2021

Baby brine shrimp, or Artemia nauplii, are a fish breeder's staple for a majority of species. Nathan Hill explains why and how you can create your own from eggs.

The most commonly touted species of baby brine shrimp is Artemia salina, but it has long been extinct. Of the seven known remaining species, the one seen by most aquarists originates from San Francisco Bay.

Baby brine shrimp is a superb food source for many fry, being riddled with protein, carotenoids and B vitamins.

Artemia come with tough chorion, or outer shells. If left on, these shells can prove fatal when ingested by small fish, clogging the intestinal tract. Hence Artemia require hatching prior to feeding.

Alternatively, decapsulated Artemia can also be purchased. These eggs, with shells removed by acids, are kept in liquid suspension until needed. These can be fed directly to fish, or hatched in the same way as their shelled counterparts — and their success rate can often be higher.

Hatch rates are often touted as high as 95% on many non-decapsulated brands, but the tragic reality is that in many domestic cases only around 40% yield is actually attained.

Several factors need to be considered when hatching Artemia eggs. Temperature plays a huge role, with 25°C/77°F consistently showing to be optimal for success. Salinity of water should be very high and a specific gravity of 1.030 should be aimed for at 25°C.

Water needs to be both hard and alkaline, with a pH of 9.0 favourable. Anything below 8.0 has a big impact on hatching and success rates.

The most common flaw is failing to provide a light source. Inside the Artemia egg is a chemical called trehalose which is triggered by a light source to turn into glycerol. This is a hygroscopic chemical and draws water through the membrane and into the Artemia itself, starting the hatching process.

Some Artemia have been known to hatch in the dark, but these exceptions not fully understood, and do not represent successful hatches. Adding an artificial light source to San Francisco brine shrimp is known to increase hatches by 50% or more.

To successfully produce Artemia from eggs, a volume of water needs to be vigorously aerated for movement with the eggs in it. These will hatch in the conditions as stated in around 18 hours, although a second smaller hatch can also occur afterwards.

The Artemia should be fed immediately to fry for the best nutritional effect. If attempting to enrich or feed it around ten hours should lapse — after which it will have moulted, developed a mouth and be capable of feeding on micro-organisms. Enriching before this time will be futile.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.