[Peter Finke]

In principle, licorice gouramis and chocolate gouramis harmonize very well, since they both live in the same biotopes (small running blackwater streams in peat bog rainforest areas). Therefore both prefer deeply brownish coloured water of very low conductivity (well below 100 microsiemens/cm) and a pH well below 7.0, mostly between 3.0 and 6.0. Their preference of different regions in the waterbody (chocolate in free water and near the surface, licorice near to structures as caves and the bottom area) are appropriate, too.
But: Sphaerichtys could be much more aggressive than Parosphromenus and they have different movement and feeding habits. Doubtless, one could keep them together in a tank big enough for the establishment of rather separate territories, but then it could be difficult to feed the licorice appropriately. One thing is very difficult indeed: to breed both of them extensively in such a tank because the adequate feeding of the young is nearly impossible.
Whereas chocolates are still widespread living in nature presently (especially osphromenoides), the many variants of licorice are strongly confined to mostly small surviving habitats under high pressure of imminent destruction, and therefore all of them are rare and endangered fish. They are much more specialized than the chocolates. The Parosphromenus-project has not been launched in order to make licorice popular for simple fish-keeping, but to find people all around the world to engage in their sustainment. For an aquarist this means breeding them, in the first rate, and engaging in nature conservancy in south-east Asia.
Simply buying or catching a group of this rare fish and keeping them in a nice aquarium is nothing I would recommend. Simply keeping very rare and endangered fish just for establishing a decorative aquarium is somehow besides the reality; for this purpose there are enough nice fish which are not endangered at all.
But as I described in the beginning: It could really be a very good fish-community and a nice, biologically founded tank. Therefore I would suggest the following way to proceed: First one should learn to breed the licorice (and the chocolates). If interested in endangered rare fish, in my view this is a prerequisite to everything else. That means: You should breed a pair of these fish in a suitable small tank, better two or three species in two or three small tanks. Only there you will observe the full behaviour. A year later (or so) one could have enough offspring. Then time has come to establish that nice big tank following ecological and other biological considerations. Before it’s only fun without thoughts on the circumstances.