Scientific name: Mikrogeophagus ramirezi (My-crow-gee-oh-fay-guss ram-ear-ez-eye). Size: 5cm/2in. Origin: Venezuela, Colombia, Brazil. Aquarium size: 60 x 40cm/24 x 16in footprint recommended; 70 l or more recommended. Water requirements: Soft, acidic water; 5.0 to 7.2ph, hardness below 8°H. Temperature: 26–30°C. Availability and cost: Common, price varies hugely with quality, starting from £5.