HomeCompare fishForktail rainbowfish vs Blackfin pearlfish Forktail rainbowfish vs Blackfin pearlfish: can they live together? Verdict: Not recommendedThe Blackfin pearlfish is best kept in a species tank.The Blackfin pearlfish is aggressive towards other fish.Their temperature ranges only just meet, at 24°C (75°F).A pH of 6.0–7.0 suits both.Side by sideForktail rainbowfishBlackfin pearlfishAdult size5 cm (2 in)7 cm (2.8 in)Minimum tank75 L (20 US gal)55 L (15 US gal)Temperature24–26°C (75–79°F)18–24°C (64–75°F)pH6.0–8.06.0–7.0Hardness5–12 dGH (89–214 ppm)5–12 dGH (89–214 ppm)TemperamentPeacefulAggressiveCommunity tankGoodNot suitableCare levelEasyModerateDietOmnivoreCarnivoreSpecies profilesForktail rainbowfishPseudomugil furcatusBlackfin pearlfishAustrolebias nigripinnis