[iii]{}\] 18.7 and 33.5 $\mu$m, \[S [iv]{}\] 10.5 $\mu$m, and \[Ne [ii]{}\] 12.8 $\mu$m. PAH features at 6.2, 7.7, 8.6, 11.2, and 12.8 $\mu$m are also present. The PACS spectrum also shows bright FIR lines, especially \[O [iii]{}\], \[C [ii]{}\], \[O [i]{}\] 63 $\mu$m, and \[N [iii]{}\]. The \[O [iii]{}\] line is the brightest of all, with \[O [iii]{}\]/\[C [ii]{}\] = 2.4. While \[C [ii]{}\] is the brighest FIR fine-structure line in normal and dusty starburst galaxies [@brauher-2008], we find that this is often not the case in low-metallicity dwarf galaxies [@hunter-2001; @cormier-2010; @cormier-2012b; @madden-2012b].

The young star-forming nature of this galaxy also agrees with intense \[Ne [iii]{}\] (41.0 eV), \[O [iii]{}\] (35.1 eV), \[S [iv]{}\] (34.8 eV), and \[N [iii]{}\] (29.6 eV) lines observed, arising from relatively highly ionised regions. \[O [iv]{}\] (54.9 eV) at 25.9 $\mu$m, which requires a relatively hard radiation field (Sect. \[sect:xrays\]), is also detected. The \[Ne [iii]{}\]/\[Ne [ii]{}\] ratio is 3.5, \[S [iv]{}\]/\[S [iii]{}\] is 0.9, and \[N [iii]{}\]/\[N [ii]{}\] is 8. These ratios are indicative of a hard radiation field typical of BCDs [@thornley-2000; @madden-2006]. While \[C [ii]{}\] can come from both the diffuse ionised phase and the neutral phase, \[O [i]{}\] traces 