http
/direktori.o-fish.com/data/505/1M_spechti.jpg Is this the black paradisefish you are reffering to? The name is
macropodus spechti (the valid name for what has often been reffered to as
macropodus concolor,
macropodus opercularis spechti or
macropodus opercularis concolor).
Like the 'common' paradisefish, these get to 3", with large males capeable of getting to 4" and females generaly always staying slightly smaller. None of these fish should realy be kept in a 1 gallon bowl. Paradisefish are remarkably hardy and can thrive in the most ridiculous environments, but it's nice to give them some extra space to swim around. They grow larger and are more active than bettas and even bettas shouldn't realy be kept in anything smaller than 2-2.5 gallons.
Keeping one in the larger tank also isn't an option. Paradisefish can be very aggressive, especialy the males, and are likely to attack other gouramies - so the pearl would be at risk. Also, the paradisefish, while able to hold its own with medium-sized fish and, despite its often boisterous nature, would not be able to handle a fully grown leporinus.
Actualy, I'm quite worried about your pearl as it is. How large are your leporinus? As you must know, leporinus get quite big, they can also be unpredictable and aggressive. Pearls are very peaceful fish, often preffering to be in the company of their own kind. A pearl won't stand a chance if one of your leporinus decides to attack it. I'd feel much better if it were moved to a more suitable, 'safer' environment.