HomeCompare fishBlackline rasbora vs Harlequin rasbora Blackline rasbora vs Harlequin rasbora: can they live together? Verdict: CompatibleBoth are comfortable at 22–25°C (72–77°F).A pH of 6.5–7.0 suits both.Minimum tank for the pair: 115 L (30 US gal)Side by sideBlackline rasboraHarlequin rasboraAdult size5 cm (2 in)4 cm (1.6 in)Minimum tank115 L (30 US gal)55 L (15 US gal)Temperature22–26°C (72–79°F)22–25°C (72–77°F)pH6.5–7.05.0–7.0Hardness5–12 dGH (89–214 ppm)5–12 dGH (89–214 ppm)TemperamentPeacefulPeacefulCommunity tankExcellentExcellentCare levelEasyEasyDietOmnivoreOmnivoreSpecies profilesBlackline rasboraRasbora borapetensisHarlequin rasboraTrigonostigma heteromorpha