Pair of Powder Blue Tangs

[Guest Timfish]

Here's a couple of Powder Blue Tangs I paired off for DaM.   The larger one sometimes "bobs" like I've seen dominate male chromis do to mark their territory but it will still be at least a couple years before we'll know if they are sexually compatible.  I used a 60 gallon QT with egg crate separating it into three sections  A large Powder Blue in the center with a medium on either side.  After a couple weeks the egg crate was shifted slightly so the mediums could swim into the middle section with the large but the large could not swim into either of the mediums section.  It only took less than a week for one of the two mediums to get very aggressive with the other medium and the egg crate had to be isolating the submissive medium.  After another month with the large and dominate medium swimming together they were added to DaM's system.

https://youtu.be/DCvXoujdhjg

[Sascha D.]

Those are some really good sized tangs. How did you make a determination on the sex since PBT are sexually uncharacteristic? I hope everything works out!

[Timfish]

Because they're not trying to kill each other. 😁

First of all none of the tang pairs in my tanks have ever been observed breeding so I can't say any of them are proven pairs like I can say with clowns.

For all practical purposes you're right about hobbiests being not being able to determine males from females as most of the tangs we deal with when we purchase them are still juviniles.  Strictly speaking though, many surgeon/tangs species do show sexual dimorphisim in size.  With Powder Blues females can be twice the size of males.  With Yellow Tangs the males can be larger than females but the size difference is much smaller than with PBs and there is more overlap between the sexes.  

Many surgeon/tang species form pairs in the wild and it's reasonable we should be able to establish pairs in our aquariums and Powder Blues are one of those species.  Additionally, I've seen pairs form with yellow tangs in my tanks over the years which raises some questions as in the wild they do not.  

The most exasperating example of a pair forming in one of my systems was when I added 3 yellow tangs to a 350 gallon system with a Purple Tang and a Sailfin Tang. The Purple almost immediatly started swimming peacefully with one of the Yellow Tangs and kept chasing off the other two Yellow Tangs.  At about 6 months it decided it had enough and spent about 4 hours one afternoon killing the two yellows it didn't like and lived peacefully with the remaining Yellow Tang for another twelve years.

Based on what I've seen over the years a significant problem with keeping multiple tangs, is groups of the same size juviniles are put together at roughly the same time.  By quarantining tangs together to see who likes who, extending the quarantine time to be sure everyone is eating and gaining weight and by get disparite sizes I have very few issues compared to 20 years ago.   

 

And individual personality can always trump anything I do. 😕