J. transcriptus is a dwarf cichlid from Lake Tanganyika in Africa. IME, they aren't overly agressive, but do defend their territory vigorously. They can be kept singly, or in bonded pairs ( you must either buy a proven pair or get 4-6 juvies and let them pair themselves usually). Since they are a rift lake cichlid, there should be plenty of rockwork in the tank, and they should only be house with fish of similiar temperment to peaceful, except their own specie which they generally do no tolerate.
IME, they get along excellent w/ N. brevis, N. leleupi, and A. calvus, but I am sure that they will get along well with most shellies and other species.
They don't get, usually, larger than 3''. Males are slightly smaller than females at maturity. They are easy to spawn if you have a good pair, but they do not directly care for their young, nor do they eat them. The young get protection by living in their parents territory, but are driven out by their parents when they are old enough.
Minimum tank size is a 10g, which could house a sole idividual or a bonded pair. With a single Juli, you may be able to keep a trio of shellies also in a 10g.
HTH