when you find blackfoot lions in the wild they are substrate attached and yes they like to dig pits which they defend.
However you'll notice i said substrate, they are always found on the bottom where the water is the coolest. The fish is consider temperate water, and yes they have made their way to the Philippines, but they always find the coolest spots.
Its unclear why they do so poorly.
Most folks can get them to eat, however, they just start dropping after a few weeks to months. I have not read about any hobbyist being successful at all w/ these fish after 4-6months.
My guess- and its only a guess- is that it has to do w/ the cool water issue, but not what you think, the collectors/ collection stations are all setup to keep tropical (warm water fish) so they collect this cold water fish and hold it for days to weeks in warm water. It gets shipped overseas at warm temps and by the time it gets here its kept warm the whole way. So I suspect your fighting the biological clock on this fish. this situation is eerily similar to catalina gobies, which are cold water fish, but kept in the holding stations and in our aquariums at tropical temps and they have much shortened lifespans.
of course there are a bunch of other theories being kicked around a well. Including higher O2 levels (cold water hold more O2 than warmer water), and a food issue (these fish actually dig into the substrate and most likely come across worms, and infauna as food additions), which we do not fed in the home aquarium.
I have read of a few folks setting up coldwater tanks for the blackfoots and even then- no succcess-hence my theory- the clock is already in motion.
Lastly, as you know a number of austrailian species make their ways to the states and these are all cold/temperature water fish (shaws boxfish, etc) yet they are collected properly, kept in the cold the whole way, and they show up doing very well, but command huge pricetags. No problem for our Japanese hobbyist who are used to paying top dollar, but well out of the range for american hobbyists
Cranberry- low to mid 60F is fine for this fish (62-65)