Known from Great Lakes Erie and Michigan with distribution extending south through the Mississippi River basin to the Gulf of Mexico drainages where it’s said to occur between the lower Apalachicola River in Florida and the Nueces River in Texas.

It may also be found in the Rio Grande which forms the border between Mexico and the United States further south where records include Falcon International Reservoir, for example.

This species’ name has been widely misapplied in the aquarium trade and hobbyist literature, most often in reference to the Southeast Asian species C. ornata, but unlike its relative is in fact very rarely exported for ornamental purposes although its is fished and cultured for food in India.

It can be told apart from C. ornata by possessing fe…

This species is also referred to as ‘royal knifefish’ in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements.

It can be distinguished from congeners by presence of many small, dark spots on the anterior portion of the body which merge to form oblique, irregular stripes extending onto the anal and caudal fins posteriorly.

This species was first imported for the aquarium hobby during the 1950s and was for many years misidentified and traded as Bedotia geayi, a valid, but different-looking congener native to the Mananjary River system, south of the range of B. madagascarensis. In terms of external characters, the two are most easily told apart by differences in colour pattern, particularly that of the unpaired fins, and some morphometric counts.

Described from ‘Rivulet in sago forest at Ngaiguli, Terangan, Aru Island, Aru Islands, Maluku, Indonesia’, corresponding to the island now normally referred to as ‘Trangan’ in the Aru Islands group, eastern Indonesia.

The islands are located in the Arafura Sea, with western New Guinea to the north and the Arnhem Land Region of Australia’s Northern Territory to the south, and though they lie within Maluku province of eastern Indonesia, are part of the Australian continent in a geological sense.

Generally found within 15-20 km of the sea but habitat-type is extremely variable. It’s been recorded in full marine conditions as well as pure freshwater environments, and commonly inhabits coastal mangrove creeks, swamps, and salt marshes.

Freshwater habitats tend to comprise lowland swamps or forest streams with clear water but some populations inhabit acidic, tannin-stained, black waters. It’s also abundant in the artificial canals typical of residential zones in the Gold Coast, southern Queensland.

This species is also traded as ‘forktail rainbowfish’ or ‘yellow forktail’, and it’s also undergone several changes in scientific name since description. Pseudomugil furcatus is the original designation, but Allen (1980) created the genus Popondetta for it on the basis of morphological characters including number of anal-fin rays (16-20 in P. furcatus, 8-12 in other Pseudomugil spp.), absence of anterior…

Given its eventual size and natural behaviour this species is largely unsuitable for the home aquarium, and we know of only a handful of private aquarists with the facilities required to house it long-term.

Unfortunately juveniles are readily available in the trade, although the scarcity of privately-maintained adults would suggest that most fail to reach their potential.