Over the course of the past couple years I’ve had a few Lightning Maroons go missing. Of course, there is the paranoid person who’d say someone is coming in and swiping them, but let’s be real for a second. You might recall the discovery of a Maroon that had traveled through my circulation pump; that one wound up dying, and surely some of the tiny brown hunks of “stuff” I’ve found on my floor over the years may well have been the end result of a Lightning Maroon or two along the way (I have covers on my cubes, but BRTs currently do not have covers).
You would think I’d learned my lesson by this point, but tonight I was doing my last round of feeding and I noticed that my holdback white stripe X white stripe pair was missing a female…what? I checked all over the floor..nope.  This actually gave me hope…I stirred up the tank a bit, still no fish.  HMM.  Well, their temporary BRT home sits directly over the sump, and sure enough, once I broke out the flashlight, there was the big girl just cruising around.
I netted her and was ready to move her back to the BRT when I stopped myself…there are 1 foot walls on the sump above the water level, while there’s only 1-2 inches about the surface of the BRT.  So….back to the sump she went, and after a few minutes her male sibling joined her down in the sump.  At some point they’ll get their own tank again…
Let this be a lesson to you – Clownfish can and do jump.  Lids on their tanks aren’t optional unless you’re willing to accept the possible outcome.