Opae Ula, Hawaiian Shrimp

Opae Ula
Opae Ula in my 5 gallon tank, picture by Clint Norwood

Opae Ula
Close up of Opae Ula in my 5 gallon tank, picture by Clint Norwood

Opae Ula
Close up - Picture by Plantlady223

Anchialine pond
Anchialine pond in South Maui - Picture by Justin Havird (Auburn University), Anchialine pond, South Maui, CC BY 4.0

Latin Name: Halocaridina rubra

Common Names:Opae Ula, Hawaiian Red Shrimp, Volcano Shrimp, Micro Lobsters

Origin: Hawaii

Size: 0.6 inch (1.25 cm)

Suggested Minimum Tank Size: 1 gallon

Preferred Temperature:
68-80°F (20-27°C), never below 50°
Special Considerations:
Opae Ula are found almost exclusively in the Hawaii Islands. They inhabit coastal pools with varying salinity called Anchialine Ponds. This constantly changing environment makes them especially hardy and adaptable.

They can tolerate salinity levels from almost freshwater to full strength seawater, maybe even stronger in a pinch. Optimum is around 1.008 to 1.012.

They require very little food or filtration. But they are easily pickings for predators. They need to be in a species tank of their own with maybe a few snails. Nerite snails are a good companion species as they can tolerate the salinity.

These are the shrimp commonly found in those little closed ecosystems. This is not recommended. Opae Ula will live up to 20 years if given optimum care. But they usually starve to death in the closed systems and rarely live more than 2 years.

After the shrimp are settled in their aquarium they will possibly start breeding. The eggs are carried around by the female until hatching. At this point they just float around like plankton for a while until by the miracle of metamorphosis they turn into tiny versions of the adult shrimp. They become sexually mature within 6 months to a year of age.

Opae Ula are a treat to keep, they are very active. They are extremely easy to feed. I feed mine about once every 3 days, just a tiny amount of spirulina powder or a 1/4th piece of an algae wafer. If they are not swarming to the food then cut back on feeding. They really don't need much. They browse on the bacteria and microscopic algae in the tank. It is much better to underfeed instead of overfeeding. You can easily keep up to 100 shrimps in a 5 gallon tank. Opae Ula are self regulating and will not over populate their tank. You can always split them up into other tanks or keep them in a bigger tank.

The meaning of their name "Opae Ula" has been hard for me to pin down. I get conflicting information. Some say "Opae" is small shrimp and "ula" is lobster. Others say it means "Opae = red, and "Ula" = shrimp. If you know for sure, please let me know.

Their bright red coloration, their active lifestyle, their ease of keeping make these one of the best aquatic pets available. They are definitely one of my favorites.
Back to Invertebrates For Your Tiny Tank