The 18-gallon close to the south-facing lanai windows.
Downsizing my opaeula hobby to 2 tanks: 18-gallon & 1.5-gallon. Keeping the 2 that require the least amount of maintenance. The 18 seems crowded, but the opae seem to be fine. I’ve seen a couple of berried females, although they don’t show up in the short video below.
For more on the 1.5-gallon, see “Experimental Oblong 1.5-gal Tank” and “Aqualifter Pump+Filter Change for Small Tanks.” The opae in the 1-gallon tank were also moved into the 18-gallon.
These remaining two tanks are healthy and require very little maintenance. I haven’t done water changes in years. I seldom need to top-off (both are hooded) and salt creep is not a problem. I’ve never had to clean the glass for the 1.5. I haven’t cleaned the 18 glass in over a year. This tank gets a lot of sun, so I may need to do a cleaning of the front panel glass when it gets too overgrown.
I’ve never fed the 1.5. Since combining the 10 and 18 colonies, I’ve been dropping tiny pieces cut from a dime-sized algae chip into the 18 once a week. I don’t think this is necessary since the algae growth in the tank is robust, but they seem to like it.
The 18 is filled to the 10-gallon level to prevent salt creep, and this arrangement seems to be working fine. For the 18, I run the UGF pump for a few hours each day. The 1.5 is still using the Aqualifter system, which runs 24/7 with a very light flow. I may need to clean the tubes when they become clogged, but they’ve been fine so far.
This DIY UGF is slightly different from the one I posted in February 2016.
Click image to enlarge.
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.
Last updated 2/19/18
Update 2/19/18: Correction: The zoeae are probably from the same batch reported on Jan. 29.