A strictly anaerobic, moderately thermophilic, halotolerant rod, designated BELH25(T), was isolated from a water sample of a Tunisian hot spring. Cells were non-motile, 2-6 µm long and 0.4-0.6 µm wide, appearing singly or in pairs. The isolate grew at 45-70 °C (optimum 55 °C), at pH 6.2-8.0 (optimum pH 7.0) and with 0-4% NaCl (optimum 0-2.0%). Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Strain BELH25(T) used cellobiose, fructose, galactose, glucose, maltose, mannose, sucrose, starch and yeast extract as electron donors. The main fermentation products from glucose metabolism were formate, acetate, ethanol and CO2. The predominant cellular fatty acids were iso-C15:0, iso-C17:0 and anteiso-C15:0. The DNA G+C content was 37.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain BELH25(T) was most closely related to Caloramator viterbiensis JW/MS-VS5(T) and Fervidicella metallireducens AeB(T) (92.2 and 92.1% sequence similarity, respectively), and the isolate was positioned approximately equidistantly between these genera. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain BELH25(T) is proposed to be a member of a novel species of a novel genus within the order Clostridiales, family Clostridiaceae, for which the name Fonticella tunisiensis gen. nov., sp. nov. is proposed. The type strain of the type species is BELH25(T) (=DSM 24455(T)=JCM 17559(T)).