I’m sorry to hear about the die off of the red feeder shrimp. If I understand the situation correctly, the 400 red feeder shrimp (Halocaridina rubra) expired in their shipping bag after you had opened it and set it in place inserted as a liner into your small aquarium bucket.
If that’s the case, then I think it’s likely that the die off was triggered by pH shock and a spike in the ammonia levels within the shipping bag after it was opened and exposed to the air. Allow me to explain in greater detail, sir.
It’s a long haul from Hawaii to the mainland and all the while the 400 red feeder shrimp are en route, they are excreting wastes and respiring in the dark shipping box — consuming oxygen (O2) and giving off carbon dioxide (CO2). That means two things: deadly ammonia is steadily building up in the shipping bag and the pH is steadily dropping, making the water more acidic.
This downward pH shift is actually helpful in that ammonia is less toxic at low pH and becomes much more toxic at higher pH. This is because ammonia exists in water in two different forms — a nontoxic ionized form usually referred to as ammonium (NH4+) and an un-ionized form (NH3), which is highly toxic. Ammonium (NH4+) is completely harmless to fish and invertebrates since the ionized ammonia molecule cannot cross the cell membrane and enter their cells. Note that only difference between harmless NH4+ and deadly NH3 is the addition of a hydrogen ion (H+) which converts toxic ammonia to nontoxic ammonium. At low pH, the extra hydrogen ions (H+) of acidic water are readily available to attach to the ammonia molecule, converting most of the ammonia to ammonium: NH3 + H+ —> NH4+. But at high pH, under alkaline conditions, exactly the opposite occurs. At high pH, the abundance of hydroxide ions (OH-) in alkaline water strips the extra hydrogen ion (H+) away from ammonium, rapidly converting most of it to deadly ammonia: OH- + NH4+ —> NH3 + H20. In other words, the higher (more alkaline) the pH, the more ammonia is present in the dangerous un-ionized form (NH3), which easily crosses cell membranes and enters the body.
This should make it easier to understand exactly what is happening in the shipping bag. As the hundreds of feeder shrimp breathe, consuming O2 and giving of CO2, the pH of the water drops and more of the ammonia (NH3) they produce is assimilated into harmless ammonium (NH4+). So the decrease in pH that occurs during long-distance shipping is actually protecting the new arrivals somewhat — until we open the shipping bag! Once the shipping bag is opened, CO2 begins offgassing from the bag water and fresh O2 begins entering the water, and as the pH begins to rise in response and return to normal, the ammonia in the water becomes increasingly poisonous. The suddenly high concentration of ammonia in the water quickly diffuses into the shrimp’s cells, and acclimating them to your holding tank becomes a race against ammonia poisoning just that quickly.
So I suspect that a sharp rise in pH resulted in ammonia poisoning as harmless ammonium was quickly converted to toxic ammonia after the shipping bag was opened and exposed to the air, and that the combination of this spike in the ammonia level and pH shock caused the demise of the feeder shrimp.
Now that your 10-gallon holding tank is fully cycled, there shouldn’t be any recurrence of this problem since you can quickly acclimate the replacement feeder shrimp to the new aquarium after you open the shipping bag, as explained below, in which case all should go well:
ACCLIMATION PROCEDURES: Be Sure to Check the specific gravity to 1.0114!!
Prepare NEW water. Do NOT rely on the water the animals are shipped in for holding these shrimp. Check that the salinity of your holding tank is the same as the shipping water. If it is not adjust your holding tank so it is the same as the shipping water BEFORE acclimating. If you do not do this you will kill the shrimp. All other parameters must be within acceptable ranges.
Please acclimate slowly. The best way is to:
1. Float the bag in your tank for about 20 – 30 minutes to equalize temperatures.
2. Then partially open the bag and add 1 cup of tank water.
3. Wait 10 minutes.
4. Remove 1 cup of water and add another cup of water from the tank.
5. Wait 10 minute.
6. Gently release the animals into the tank, discarding the water left in the bag.
7. Do not feed until the day after arrival and acclimation.
If you follow the above instructions, Lawrence, you’re new batch of red feeder shrimp will be acclimated and happily settled into their new 10-gallon holding tank within 20 minutes or so after you open the bag. This abbreviated acclimation procedure will protect them against pH shock or ammonia poisoning and you should be all set.
Here is some additional information on maintaining Volcano shrimp that you may find useful, sir:
You will find the red feeder shrimp (Halocaridina rubra) to be easy to keep and relatively undemanding to culture, although their numbers build up very gradually due to their naturally slow rate of reproduction.
Red feeder shrimp or volcano shrimp, as they are sometimes known, prefer brackish conditions and breed best at reduced salinity (1.0145-1.0168) but they adapt well to full strength saltwater and will survive indefinitely is a marine aquarium. They are a perfect "feed-and-forget" treat for large seahorses! As a rule they don’t need a great deal of room. The size of the tank you’ll need depends on the number of shrimp your dealing with and whether you want to maintain and ongoing culture or simple keep them alive until needed. A 5-10 gallon tank will generally suffice for 500-600 of these shrimp and biological filtration of some sort is desirable for keeping them long term. A simple sponge filter will do.
Here is some additional information about these shrimp that may be of interest to those of you who are interested in keeping or culturing these colorful little crustaceans:
RED FEEDER SHRIMP from Hawaii (Halocaridina rubra)
* Excellent nutritional value
* Irresistible to all the greater seahorses.
* Feed-and-Forget — lasts forever in saltwater!
* Easy to enrich.
* Simple to gut-load.
* Can be cultured using simple techniques and the most basic setups.
* Reproduces slowly; difficult to build up a large population.
Specific gravity: 1.0145-1.0168; pH: 8.0-8.3
Temperature: 68 degrees F – 73 degrees F (20 degrees C – 23 degrees C)
These fabulous little feeder shrimp can be kept indefinitely in a spare 2-10 gallon tank, or even a clean, plastic bucket, that has be filled with clean saltwater and equipped with an airstone for aeration. Neither a heater nor a fancy filtration system is required. They thrive at room temp and reduced salinity (1.015-1.016), and all they require is an airstone (or a simple air-operated foam filter at most) to keep the water oxygenated, with perhaps a little coral rubble as substrate and a clump or two of macroalgae (sea lettuce, Ogo, Gracilaria) to shelter in. They’re easy to feed — they feed primarily on algal mats and bacteria — but they will accept vegetable-based flake foods and pellets such as various Spirulina products. They are filter feeders and can also be fed with yeast or commercially prepared foods for filter-feeding invertebrates. Many people find an easy way to feed them is to place a small piece of algae-encrusted live rock in their holding tank; once they clean it off, simply replace it with a new piece of algae rock. But if you want to culture them, I’d recommend ordering the special shrimp food formulated just for them when you order your feeder shrimp from Hawaii. It’s designed to meet all their needs and requirements.
These tiny red feeder shrimp (Halocaridina rubra) are native to Hawaii where they inhabit underground lava tubes. Brackish pools collect in the cracks, crevices and depressions in the lava below the water table, thus forming the habitat for the shrimp. The brackish water that fills these pools consists of intrusive seawater diluted by freshwater that percolates downward. Because of their lava-tube habit, they are sometimes called Hawaiian Volcano Shrimp.
Native Hawaiians call them Opa’e-ula, and they are unique among the several different species anchialine pond shrimp in being small, social, herbivorous shrimp that feed mainly on algae and bacteria. They are known to feed on insects that drown in the lava tubes. When conditions are favorable, they may feed en masse at the surface in swarms of countless individuals that turn the water red.
Halocaridina rubra look like miniature, bite-size Peppermint Shrimp, and all seahorses save the miniature species go absolutely nuts for them! They are very nutritious and eat a varied, omnivorous diet. They are perfect for seahorses in every way.
Unfortunately, it is very difficult to culture these shrimp in any quantity, since they reproduce slowly and the females only carry 12 to 14 eggs. They spawn but 4 or 5 times and produce an average of only 5-10 larvae per spawn. The larvae hatch as free-swimming, yolked zoeae after a brooding period of 38 days. Larval development is abbreviated with four zoeal stages and one megalopial stage occurring before they reach the first juvenile stage. Duration of the larval stages in the aquarium is 24 to 27 days at 22 to 23 degrees C.
However, they can be purchased in quantity (up to 500 shrimp) at very reasonable prices from Hawaii, and they are easy to keep alive indefinitely, making them ideal to keep around as an occasional treat for your seahorses.
Best of luck with your next batch of red feeder shrimp, Lawrence! Your seahorses will love them!