Speaking of H. Malu's, I don't think it's any different than most speciman's. You have to start with a healthy one to begin with.
My H. Malu is almost two years old now & has been very easy to care for. It even survived being sucked into a maxi-jet the first few months I had it.
The mouth on mine has always been very tiny & tight, so if that pic shows an open mouth I'd be very wary.