Ghost CrayfishOrigin: These crustaceans are native to Florida, specifically areas east of St. Johns River. They are very hardy, and they tend to adapt well to almost any environment and can be found in many different bodies of aquatic environments. Tank Size: 20 Gallon Long+ Swim Region: Bottom Temperament: Mildly Aggressive Size: 6 inches (Males Females) Temperature: 65 75 F Water PH: 6. 5 7. 5 Water Hardness: 3 10 dGH 52 178 ppm