Oh, I see — it seems I misinterpreted your previous question about how long the gut-load the brine shrimp. My bad!
Here’s how I enriched/gut-load both newly-hatched brine shrimp and adult brine shrimp. (Maintaining gentle aeration when gutloading or enriching the brine shrimp is a good idea in order to keep the particles in suspension where they can be ingested by the shrimp):
It’s best to either feed bbs (Artemia nauplii) to your seahorse fry immediately after hatching, when their yolk supply is virtually intact and they have their maximum nutritional value, or feed bbs that are 2-days old or older (2nd instar Artemia) that have been enriched prior to feeding.
Enriching Brine Shrimp at Advanced Instars
Feeding baby brine shrimp his the key to raising nutritious nauplii for your juvenile seahorses. Newly hatched brine shrimp deplete their yolk supply within 6-8 hours and must be fed regularly thereafter to maintain their food value.
Fortunately, brine shrimp are filter feeders and will take in whatever is suspended in water with them. This makes it easy for the aquarist to load the shrimp he is raising with nutritional value by giving them a healthy diet supplemented with special food additives. Commonly used foods for culturing Artemia include unicellular algae; rotifers; yeast-based emulsions; micronized egg yolk, rice bran, wheat flour or whey; and dried Spirulina algae.
Research has proven that brine shrimp can be further enriched by adding supplements such as cuttlefish liver oil, cod liver oil, corn oil, fat-soluble vitamins, amino acids, and mineral formulations to their culture water. Analysis of the nutritional content of culture animals after they had been exposed to such supplemental additives showed a dramatic increase in long-chain fatty acids and many vitamins.
Rather than experimenting with your own concoctions, I recommend using one or more of the lipid-rich food concentrates which have recently been developed specifically for use in aquaculture. Products commonly used by professional breeders for fortifying brine shrimp nauplii include Beta Meal, amino acid and essential vitamins (liquid multi-vitamins), commercial products of (W3) highly unsaturated fatty acids such as Vibrance 1, Selcon Concentrate, Selco, Culture HUFA, Roti-Rich, Astaxanthene biological pigment Natu-Rose, AlgaMac 2000, MicroMac 70, and unicellular microalgae cultures (e.g., T-iso, T-weiss, and Nannochloropsis, Chlorella and Isochrysis sp.). Such products are typically rich in amino acids, highly unsaturated fatty acids (HUFA) and vitamins, which makes them ideal supplements for culturing Artemia. Very often, using a combination of these enrichment products provides better nutrition and produces better results that relying on any one product alone.
For best results, 24 hours after the culture tanks are seeded with newly hatched brine shrimp, begin feeding the nauplii sparingly by adding a concentrated food supplement or enrichment formula according to the instructions. Adjust the amount so that a slight haze barely clouds the water for a few hours every day. Do not feed again until the water is crystal clear and do not overfeed. As the brine shrimp grow, you may need to adjust the dosage of your enrichment formula.
Fortifying 1st-instar Artemia Nauplii (newly hatched baby brine shrimp)
Artemia nauplii (baby brine shrimp) are filter feeders that will ingest whatever is suspended in the water with them. This makes it easy to enrich the nauplii with everything from yeast cells to microalgae to fatty acids and vitamins and minerals as discussed above, greatly enhancing their nutritional profile in the process.
The problem with such traditional enrichment methods is that only older nauplii at advanced stages of development can be fortified this way. Newly hatched brine shrimp nauplii (1st instar) lack mouthparts and derive their nourishment from a yolk sac. They are incapable of ingesting particles in the water. Consequently, only bigger nauplii that have molted once or twice (2nd instar and beyond) are suitable for this type of enrichment. This is a serious drawback since these older, larger Artemia nauplii have already grown beyond the size that most newborn seahorse fry are capable of swallowing.
Hobbyists with seahorse fry that are unable to take 2nd-instar Artemia nauplii as their first food usually get around this problem by offering newly hatched brine shrimp nauplii obtained from decapsulated cysts. These 1st-instar Artemia nauplii are fed to the fry as soon as possible after hatching while the baby brine shrimp still retain as much of their yolk sac as possible.
However, there is a better alternative that combines the best of both techniques, making it possible to provide seahorse fry with bite-sized, enriched Artemia nauplii that contain most of their yolk supply. This is accomplished by decapsulating Artemia cysts and refrigerating the newly hatched brine shrimp at a temperature of 41-45 F (5-7 C) for 24-36 hours when the nauplii are still between 12-16 hours old (Mai 2004b). Cooling down the nauplii to such temperatures slows down their growth and metabolism to a virtually standstill, and they can then be enriched continually for the next 2 or 3 days while they remain in a state of arrested development (Mai 2004b). They will not grow or molt during this period, keeping the Artemia bite-sized and allowing the inactive nauplii to retain the bulk of their yolk as they undergo enrichment (Mai 2004b). Supplements rich in high unsaturated fatty acids (HUFA) and vitamins and minerals are typically used to fortify the refrigerated nauplii (Mai 2004b).
Although the Artemia nauplii do not eat and cannot actively feed while in this state of suspended animation, the prolonged period of immersion in this nutrient soup allows them to gradually absorb the enrichment nonetheless (Mai 2004b). Whether the concentrated nutrients slowly infuse their bodies or merely coat the nauplii or both is uncertain, but there is no doubt about the superior results this method of enrichment can produce (Mai 2004b).
Rolf Hebbinghaus was one of the first to develop the refrigeration method of fortifying Artemia nauplii at the Lubbecke-Aquazoo in Dusselfdorf, Germany (Mai 2004b). Wolfgang Mai has since conducted a series of tests on H. fuscus fry, which demonstrated that the young receiving the enriched Artemia enjoyed significant advantages in length, girth and vigor compared to the control group of fry which received newly hatched brine shrimp nauplii that had not been enriched (Mai 2004b).
And here are the specific instructions for feeding the baby brine shrimp you hatch out with ArtemiaGro and for enriching the adult brine shrimp with Vibrance I:
Ocean Rider Artemiagro
This dry product is also a trade secret and has been specifically formulated for growing and/or maintaining healthy populations of artemia (brine shrimp) and/or rotifers. It is very high in vitamins, minerals, fatty acids, and digestible proteins that optimize growth and survivability.
Please store in a cool dark place (refrigerator or freezer is fine).
For fast and efficient feeding: Blend for 2 to 3 minutes 1 tablespoon of Ocean Rider Artemiagro into 1 cup of fresh water. Store any unused portion in the refrigerator. Add to artemia/rotifer grow out vessel until water turns slightly murky. When the water has cleared you may add more. Store any unused portion in the refrigerator in a container that does not allow light to penetrate. For slower and alternative feeding : Simply sprinkle a small amount directly into artemia vessel until water turns slightly murky. Re-apply when water has cleared. (Be careful not to stir up the bottom of vessel.)
Enriching Artemia with Vibrance I
For enriching or "gut packing" live Artemia (brine shrimp), or other live shrimp or live food of all sizes. Blend 1 teaspoon of Vibrance into 1 cup of water for 3 minutes. Add this to the live food vessel for 30 minutes, or until you see the gut of the animal turn red. Rinse the animals with clean salt water and feed immediately to your seahorses or other fish.
When I am gutloading adult brine shrimp either to bioencapsulate medications or to enrich the brine shrimp hired to feeding I soak them in freshwater for around 30 minutes as explained below.
Soak the adult brine shrimp in freshwater treated with the antibiotic or the enrichment formulation of your choice for 15-30 minutes and then feed the gut-loaded shrimp to your seahorses immediately. (Don’t let your pumps and filters "eat" all the brine shrimp!)
The brine shrimp are soaked in freshwater, not saltwater, because in theory the increased osmotic pressure of the freshwater helps the antibiotic solution or enrichment product move into their bodies via osmosis. But in fact nobody knows for sure whether the antibiotic/enrichment is diffusing into the brine shrimp or they are ingesting it in very fine particles (brine shrimp are filter feeders and will take in whatever is suspended in the water with them) or whether the brine shrimp merely become coated with the medication or enrichment formula while they are soaking in it. But that’s not important — all that really matters is that gut-loading adult brine shrimp in this manner is very effective.
Best wishes with all your fishes, Seagazer!