Taxonomy:
(Sultana, 2010)
Scientific Names:
1. Tichogaster lalius (Hamilton, 1822)
2. Colisa lalia (Hamilton, 1822)
3. Colisa lalius (Hamilton, 1822)
4. Colisa unicolor (Cuvier, 1831)
Common Names:
The English names for this species are, the Dwarf Gourami or Red Gourami. In Bangladesh, this fish is known as, the Ranga Khailsha, Baicha and the Lal Khailsha. (IUCN Bangladesh, 2000).
Morphology of the Dwarf Gourami
The Dwarf Gourami has a compressed egg-shaped body. It has a small mouth, which is directed upwards and a soft dorsal fin, with a pair of pelvic fins in the form of a long, filiform ray. The Dwarf Gourami’s caudal fin is rounded and in certain individuals it may be notched. The lateral line of this freshwater organism is incomplete. It has a characteristic red spot on the caudal and dorsal fin, as well as a reddish colour, with double rows of scarlet and slight light blue spots forming oblique stripes. Its pelvis is also characterized with a hint of orange (Rahman, 2005). The male and female are not as easy, as in live-bearing species, to differentiate. The males are usually smaller than the females, whilst the females have more rounded bellies than the males. However the most distinctive difference, is the dorsal fin. The male's dorsal fin is longer, while the female's is more rounded and shorter (Sharpe, 2018).
Habitat and Distribution
This species is found in Bangladesh, Nepal, Myanmar, India and Pakistan. It is widely distributed and it is classified as “Least Concern” on the IUCN Red List. The Dwarf Gourami inhabits freshwater systems such as streams, rivers, beels, boars, ponds, rice fields, stagnant water, ditches, floodplains and canals. These are omnivorous fish and feed on aquatic plants and insects found in shallow aquatic vegetation. This species generally breeds during the monsoon season. The male Dwarf Gourami, builds bubble nests, however it devours the fry, 2-3 days after they are born (IUCN Bangladesh, 2000).
Threats Faced by Dwarf Gourami
The main threat faced by these species is the aquarium industry, however, they thrive very well in freshwater aquaria. In fact in Calcutta, these fish are placed in water bottles and they are sold for ornamental purposes. It is one of the most beautiful fish of its genus and is a favourite amongst aquarists. This fish is also captured in subsistence fisheries, and it is consumed by communities that live around different water bodies, such as rivers and lakes (Vishwanath, 2010). It is also captured for its use in ponds, since it feeds on the larvae of mosquitos (Sultana, 2010).
In the 1980s, aquarists diagnosed this species with a number of untreatable diseases, most commonly mycobacterial diseases. One of these diseases, known as the iridovirus has impacted several Dwarf Gourami fish farms in Asia (Practical Fishkeeping, 2016).
Unfortunately, there are not enough conservation studies on this species, since proper threats of these species and the aquarium trade impacts need to be clarified (Vishwanath, 2010). It is essential that more ornamental aquaculture is carried out, in order to conserve the Dwarf Gourami.
References:
Hamilton, F. 1822. Fishes of the Gganges. Archibald constable and company, Edinburgh. p. 120.
IUCN Bangladesh (2000) Red List of Bangladesh: Volume 5: Freshwater Fish [online], Available at: https://portals.iucn.org/library/sites/library/files/documents/RL-549.3-003-v.5.pdf, (Accessed on: 20/11/18).
Practical Fishkeeping (2016) Let’s Hear it for the Dwarf Gourami [online], Available at: https://www.practicalfishkeeping.co.uk/features/articles/lets-hear-it-for-the-dwarf-gourami, (Available at: 20/11/18).
Rahman, A.K.A. 2005. Freshwater Fishes of Bangladesh. The Zoological Society of Bangladesh, Dhaka. pp. 281-282.
Sharpe S. (2018) How Can I tell if a Gourami is Male or Female [online], Available at:https://www.thesprucepets.com/how-do-i-sex-a-gourami-1380970, (Accessed on: 18/11/18).
Sultana S. (2010) Dwarf Gourami: Trichogaster lalius [Colisa lalius] [online], Available at: http://en.bdfish.org/2010/02/dwarf-gourami-colisa-lalius/, (Accessed on: 18/11/2018).
Vishwanath, W. (2010) Trichogaster lalius. The IUCN Red List of Threatened Species 2010: e.T166445A6210533. http://dx.doi.org/10.2305/IUCN.UK.2010-4.RLTS.T166445A6210533.en. (Accessed on: 20/11/18).
Image references:
Image 1: Real Aquatics (2017) Dwarf Gourami Male [image], Available at: https://www.realaquatics.co.uk/dwarf-gourami-male.html, (Accessed on: 20/11/18).
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