HomeCompare fishRed rainbowfish vs Gulf gambusia Red rainbowfish vs Gulf gambusia: can they live together? Verdict: With cautionThe Red rainbowfish grows about twice as long as the Gulf gambusia; watch for bullying or predation.Both are comfortable at 22–25°C (72–77°F).A pH of 7.0–7.8 suits both.Minimum tank for the pair: 150 L (40 US gal)Side by sideRed rainbowfishGulf gambusiaAdult size12 cm (4.7 in)5 cm (2 in)Minimum tank150 L (40 US gal)20 L (5 US gal)Temperature22–25°C (72–77°F)22–25°C (72–77°F)pH7.0–8.06.5–7.8Hardness9–19 dGH (161–339 ppm)–TemperamentPeaceful–Community tankGoodGoodCare levelEasy–DietOmnivoreOmnivoreSpecies profilesRed rainbowfishGlossolepis incisusGulf gambusiaGambusia vittata