Volcanic Shrimps

FAQs about volcanic shrimps

What are marimo moss balls?

Marimo moss balls translate to “Seaweed balls” in Japan. They are actually not moss, but algae that grows in a spherical shape.

They are found only in certain parts of the world, namely lakes in Japan, Scotland, Iceland and Estonia.

Marimo moss balls in Lake Akan, Japan

The circular motion of the water currents keep them circular in shape.

What's their significance?

The balls are gifted for good luck. They are also popular as gifts between lovers and amongst friends and family to signify the tight bond between them. Some Japanese even keep them as heirlooms as they can grow up to 200 years.

What are volcanic shrimps?

Volcanic shrimps are found only in Hawaii. They are called "Opae ula" in hawaiian, with "Opae" meaning shrimp, and "ula" meaning red.

They are also nicknamed "Supershrimp" because of their hardy nature. In the wild, they can live up to 20 years and remain tiny throughout!

You do not have to feed these shrimps because they feed on microalgae in the tank. And in doing so, they keep the tank clean so you don't have to clean it often. Frequent water changing, air pumps, filters are also not required.

Opae ula lives in anchialine pools, which has a salinity in between saltwater and freshwater.

Seawater seeped from below the ground and rainwater feel from the sky, resulting in brackish water. They cannot survive in tap water as it contains chlorine.

The symbiotic relationship between marimo moss balls and volcanic shrimps

Marimo moss balls are kept together with volcanic shrimps because they trap light and photosynthesise, giving out oxygen for the volcanic shrimps. They also absorb nitrates.

In return, the volcanic shrimps give out waste materials and carbon dioxide which helps the marimo moss balls to make food.

Although the shrimps do not feed on the algae per se, the moss balls contain micro bacteria film which the shrimps feed on.

What's the maximum no. of shrimps I can put in my container?

For S sized aquarium, 5 shrimps. For M sized aquarium, 10 shrimps.

What's the life cycle of opae ula?

Where can I place my aquarium?

You may place your aquarium under medium or low light, as too much light will cause algae to grow very fast Ideal temperature is 20-25 degree celsius.

DO NOT place under direct sun or next to the window:

Place under medium light i.e. at least 2-3 metres away from the window, or under low light i.e. on shelves or corners where most light is blocked

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What do I do when water level is low?

Keep lid closed at all times to slow down evaporation. But you can buy brackish water (version for topping up) from our website when the water is less than 60% of the tank and it’s affecting the amount of space the shrimps have for swimming.

Do I have to feed the shrimps?

At the start, the algae in your aquarium have not grown, so to avoid the shrimps dying from hunger, we have packed some shrimp pellets for you. You can put 1 pellet per shrimp per month into the aquarium. After you spot algae, you can stop feeding them the pellets, because any shrimp pellets not consumed by the shrimps, pose a risk of water contamination, and should therefore be minimised.

Unless you don’t see any algae spots growing in your aquarium, e.g. due to placing it at a location with 0% sunlight (because algae requires sunlight to grow), then you can continue feeding the shrimps the pellets. You may purchase the shrimp pellets from our website.

Besides the shrimp pellets, do not drop any fish feed or other food pieces inside the water.

Do I have to switch on the light?

Do not switch on the light for more than 30mins every day because it might lead to algae growing very quickly.

Will the shrimps grow larger?

Yes they will. Like most crustaceans, they shed their old shell when they grow bigger. Opae ula moult several times in a year. If you see transparent looking shells in your aquarium, it means your shrimps have grown! They will however still look tiny.

How do I know the sex of my shrimps, and how to have baby shrimps?

It’s hard to tell the sex of the shrimps due to their tiny size. One way to increase the likelihood of them breeding would be to have more shrimps – at least 5. Then it increases the possibility of there being both males and females in the lot. The shrimps have to feel comfortable in the water, and there has to be hiding places in order for them to breed.

How often do I have to clean my aquarium?

The shrimps doesn’t mind algae because it’s food for them. But if the algae becomes so much that it affects the aesthetics of the tank, you can choose to clean it. If you wish to slow down the growth of algae, you can place it at a location that’s not too bright.

How do I clean the aquarium? (Light maintenance)

Conduct light maintenance once you see an algae patch, to prevent it from spreading

Light maintenance removes the algae without a water change. Use paper towel to remove algae from the inner surface of the container. Scrub figurines under tap water before putting them back into the water.

For detailed video instructions, click

here.

How do I clean the aquarium? (Heavy maintenance)

Conduct heavy maintenance once more than 50% of the aquarium is filled with algae

Purchase brackish water from us to conduct a full water change. Scrub the contents clean, reassemble your aquarium, then pour the shrimps back in.

For S aquarium, you’ll need only 1 bottle of 500ml brackish water. For M aquarium, you’ll need 2 bottles of 500ml brackish water. The expiry of the brackish water is about 2 years from the time you receive it.

For detailed video instructions, click

here.

Unfortunately, out of our several attempts to check with our suppliers who are professional breeders of opae ula using photos from customers, they are also mostly unable to pinpoint the exact reason why the shrimp(s) died. Reason being the shrimps are too tiny for them to investigate the issue, and also we can't bring them to a vet.

Why did my shrimp die? (1 shrimp only, within a week)

If there is only 1 shrimp that's dead out of the pair or the lot, it's most likely not an issue with the water or set up, but the shrimp itself. For e.g., it might be because of the shrimp's poor health, or their lack of ability to adjust to this new environment.

Why did my shrimp die? (all shrimps or more than 75%, within a week)

If majority of the shrimps are dead, it is most likely due to water contamination. It might be because of too much chlorine from traces of tap water that was used to wash the base rocks and decorations. Or it could be due to the introduction of figurines whereby colour was painted on the surface. If you wish to introduce any figurines, the colour of the figurine should be in the plastic itself and not painted onto the surface. It would also be recommended to use seashells or figurines made of natural materials such as terracotta, glass, sand.

Another reason could be due to the water level being too high, that the shrimps start to nibble on the brown cork.

Or it's also worth a check if any of your housemates introduced any tap water, food or foreign substance into the aquarium without your knowledge.

Why did my shrimp die? (1 shrimp only, after 3-4 weeks)

This could be due to the poor health of the shrimp, or insufficient food. Right after the aquarium is built, there is no algae in the system yet, so our instructors and information pamphlet will advise you to drop in 1 food pellet per shrimp. But once you see algae, you can stop feeding the pellets because any food left uneaten will lead to water contamination.

Some people might place the aquarium at a location with 0% sunlight e.g. bedroom make up table, or dark toilet, where algae doesn't grow since there's no sunlight. For such cases, you have to continue feeding 1 pellet/shrimp/month to ensure the shrimp has food.

Why did my shrimps die? (all shrimps or more than 75%, after 3-4 weeks)

If majority of your shrimps died after 3-4 weeks, it is most likely due to water contamination, or it could be due to the build up of nitrite over time from the shrimp waste.

Any reason could be due to too much algae. The shrimps have a love hate relationship with algae. While algae is their food, it releases carbon dioxide at night and compete with the shrimps for oxygen. Thus, if your aquarium is more than 50% filled with algae, we'd recommend you conduct heavy maintenance.

We'd recommend you conduct heavy maintenance whereby you discard all current water and dead shrimps, and wash and dry the base rocks and decorations under the sun, before assembling them back again with brand new brackish water.

If there was any foreign object bring introduced earlier e.g. a figurine that's not from our shop, we'd suggest not putting that back into the aquarium.