Opae’ula Post-Larval Stage

The opae’ula pre-adult development cycle lasts approximately 11.5 weeks. The brooding period is 38 days. The larval stage involves two substages: zoea (17 days) and megalopa (11 days). The final stage before adulthood is juvenile (14 days). Adults are theoretically able to live more than 20 years.

In the larval stage, the opae are limited to moving vertically only or hanging suspended in the water. They remain upside down, with their head pointed down and tail pointed up. In the post-larval juvenile stage, they begin to move horizontally and diagonally. In this video, we see them (tiny dots) just beginning to swim sideways on their own.

Keep an eye out for a berried female. There are three or more in this tank. Females can produce more than once per year.

Acknowledgment: Soundtrack “Alta Loma Terrace” by Wes Hutchinson.

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4 Responses to Opae’ula Post-Larval Stage

  1. Ann says:

    Good information! Thank you!


    • JimS says:

      You’re welcome, Ann. I gleaned these from a number of sources. The times need to be confirmed by closer observation. More studies need to be done on these fascinating little guys. Because of the isolation of colonies in far-flung locations, distinct variations have developed. (Of course, the mystery is how they got from one point to another hundreds if not thousands of miles away.) There’s an ongoing effort, I think, to preserve the uniqueness of each colony, but widespread distribution via sales may be leading to interbreeding and the eventual loss of geographical differences. I purchased my initial population of opae’ula from a local pet shop but didn’t think to ask where they were from. I assumed they were all the same regardless of place of origin. So I don’t have a clue where mine are from. I’m assuming the Big Island.


  2. Nate says:

    I received an Ecosphere two years ago for Christmas. A few weeks ago, while cleaning, my Ecosphere fell and shattered. I was able to quickly scoop up some of the water and shrimp and placed them into a jar. I frantically began researching how I could save these little ones and zipped to the store to buy supplies. Now, after learning how inhumane and terrible Ecospheres actually are, me breaking the Ecosphere seems like a good thing!

    They’re in a bigger, healthier and happier tank now with plenty of food and room to explore. Their red color has returned and I have my fingers crossed for breeding possibilities in the future. Anyways, that’s my story for these awesome shrimp. Thanks for all of your information. You’ve been a good resource.


    • JimS says:

      Congrats, Nate. We have a lot in common. I was first attracted to the little guys a few years ago when I saw them in a tiny ecosphere in my dentist’s office. I decided to create an ecosphere of my own. In the process of researching how to do it, I learned that it would be in humane. So I started a tank instead. And what a fun hobby it’s turned out to be. The best way to gauge the health of your tank is to monitor the opaes’ level of activity. They’re lively and always in motion when conditions are healthy. They’ll also begin to breed. When activity drops to the point where you don’t see them swimming and moving about as much as they used to or if you see fewer opae, then consider a partial water change. Also consider the location of the tank (relative to natural sunlight) and move it to see if that makes a difference. Also study the mechanical filtration system if you’re using one. Is the current too strong? Should it be turned on only intermittently? Finally, you may not need to feed than once the tank ecosystem is in balance. Beat wishes on your tank! -Jim


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