Carinotetraodon Imitator

''Carinotetraodon imitator'', commonly known as the dwarf Malabar pufferfish, is a freshwater pufferfish found in the Western Ghats of India, with little information available on its complete distribution. It is one of the smallest pufferfish in the world, and closely resembles the related '' Carinotetraodon travancoricus''.

Description

''C. imitator'' has a maximum recorded standard length (SL) of , making it one of the smallest pufferfish in the world. The species is sexually dimorphic. Males have bodies and fins which are dirty yellow to orange in colour and are covered in dark blotches. The ventrum is dirty white to dirty yellow, becoming brownish toward the midventral line and forming a stripe from their lower lip to their caudal peduncle, surrounding the anal fin, where the stripe is broader and darker. An erectable skin keel along the ventral and dorsal surfaces is present in males. Females also possess the dark spots and blotches. The body of females is light brown to beige with a white ventrum. They lack the midventral stripe, but the area around their anal fin is darker and sometimes extends as a short stripe to the lower half of the caudal fin base. The patterns and colouration varies between individuals of both sexes, and their dark spots may be conspicuous or faint or broken into several smaller spots.

Distinguishing from ''Carinotetraodon travancoricus''

''C. imitator'' can be distinguished from its congener, as the males have brighter yellow colouration and have smaller, faint blotches compared to males of ''C. travancoricus'', and lack the iridescent blue lines behind the eye. Females have smaller and fainter body blotches than ''C. travancoricus'' females, in addition to a number of small spots, though females of ''C. tranvancoricus'' may also have small spots between their larger, darker blotches. The most notable difference, however, is the body spination, which is greatly reduced in ''C. imitator'' compared to ''C travancoricus''.

Distribution and habitat

In 1999, the species was first described based on specimens in an aquarium in Germany. Information gathered through the importer from the exporter indicated that the species originated in India, and was found in small rivers in Kochi, probably from Ernakulam and neighbouring districts. The specimens were being kept with a number of ''C. tranvancoricus'', suggesting either the two species occur together, or were later mixed by collectors or exporters. They have since been found in mid- and lowland reaches of Kumaradhara and Addahole, Netravati River basin in Karnataka, as well as shallow streams. They inhabit bodies of water with sand, gravel, or stones making up the substrate. There is no information on its complete distribution.

Reproduction

Reproduction of ''C. imitator'' has been observed only in captivity. During observation, the water was kept slightly brackish, with of sea water per of freshwater, and its temperature fluctuated between . During courting, males erect their keels and their bodies become bright yellow to orange and without marks. They court females while chasing away other males. Males attempted to attract females to the spawning site by swimming back and forth between the female and the site, sometimes trying to push the female toward the spawning site. Females ready to spawn would follow the male to the site, and spawning occurred in java moss