Madagascar Rainbow

Most Madagascan rainbows in shops have been carrying the wrong label for decades. The species is still traded as Bedotia geayi, a real but different fish from the Mananjary system further south. The fish comes from short coastal streams and lower river reaches in the Atsinanana region of eastern Madagascar, many of them linked by the Canal des Pangalanes.

It reaches 10 cm standard length. An aquarium base of at least 120 by 30 centimetres is recommended for swimming space. Wild stream measurements of 23-32 °C and pH 4.5-7.5 describe observations from its habitat; choose stable aquarium conditions suited to the stock being kept.

Keep eight or more. It is a schooling species, and males show their best fins and colour while competing for females, which a pair in a small tank will never do. It is also intolerant of accumulated waste, so weekly changes of a third to a half of the volume are part of the deal. Feed small live and frozen foods alongside dry, and avoid housing it with other Bedotia species, which it will hybridise with.