The peaceful Jaloof Confederation was located deep within the unexplored (by the Imperium) regions of the Eastern Fringe. They maintained cordial relations with their distant neighbors of the Tau Empire along with limited trade. Unfortunately the Jaloof were easy prey for the then strengthening Hive Fleet Gorgon, with only the smallest fraction of their population surviving the onslaught and destruction of their worlds. Escaping in a few small, ragged flotillas to Tau space. 

'...cry havoc and let slip the muppets of war!'

Indeed, some of the Tau Water caste have theorized that it was their Jaloof neighbors who had inadvertently lead the Hive fleet directly to the Tau, but they've not been held to blame and all accusations of such have been suppressed. Such are the ways of the Greater Good. Following the destruction of Gorgon, the scant few thousand Jaloof survivors left were resettled within the protective realm of the Tau Empire.

That's a lot of gear for those little legs to hold up...

Shattered psychologically and on the verge of extinction, the majority of the remaining Jaloof have found both their niche within the Empire, as well as a degree of mental solace in the production and distribution of wholesome, educational video-programming, with which they entertain the youth of the various Tau castes. A few somewhat unhinged individuals however, embittered by their losses have taken a different path and fight to defend the last dregs of their species, alongside the Tau's Fire caste warriors.

Looking down upon the remains of the infamous Hoominz ,
against whom their Tau allies have fought both with and against.

Possessed of a shockingly light build (enough to make an Eldar look rotund!), the Jaloof are a species ill suited for war. However their long legs aid them well in advancing (and retreating) quickly. As such, they're currently training with both Fire Warriors and Pathfinders, though they have yet to prove themselves in battle...