Wise words. This species was believed to be extinct in the wild until 2011. The following excerpt from my profile explains this for those interested.
Epalzeorhynchos bicolor
Family: Cyprinidae
Common Name: Red Tailed Shark
Origin and Habitat: Originally widespread over the Chao Phraya basin and possibly the Mekong system. Previously believed to be extinct, in 2011 it was listed by the IUCN as critically endangered and considered probably extant but unconfirmed in the Chao Phraya in Thailand (IUCN 2022).
In 2011, Dr. Chavalit Vidthayanon assessed that the species is still extant in the Chao Phraya Basin but strictly localized, nevertheless, its location is still unclear (Kulabtong, et al, 2014). In the same year, the population of E. bicolor was reported to be extirpated in the Maeklong Basin and Bangpakong Basin (Vidthayanon, 2011). At present, the occurrence of E. bicolor in the wild is certainly confirmed in the Lower Maeklong Basin, Kanchanaburi Province, West Thailand, whereas it is still unclear in the Chao Phraya Basin due to the lack, to date, of documented evidence (Kulabtong, et al, 2014).
This fish lives in gaps between the rocks and its habitat is characterized by large rocks and a sandy bottom. This area is fast flown by tides and the depth of water is more than 1 meter (Kulabtong, et al, 2014). All exports of the fish are captive bred.
Compatibility/Temperament: Not a general community fish especially for beginners. Very aggressive with its own species (it probably lived in solitude except when breeding) and as it matures is often aggressive with other fish especially those resembling it and those with vertical stripes. Should be kept solitary (one fish per tank) with carefully-selected upper-level tankmates like the larger barbs (non-vertical stripe species) and rasbora. Bottom fish (loaches and most catfish, and cichlids) should not be included with this species. This fish is ex[ported by the thousands from captive breeding in outdoor ponds in Thailand, but there are few if any confirmed reports of spawning in aquaria; this may well be due to the fish's aggressiveness which cannot adequately play out in an aquarium as it does in the wild.
Discussion
A strikingly attractive fish, though one usually with a tenacious attitude. It requires a large aquarium with several good hiding spots. A good water flow from the filter will be appreciated by this fish. It is intolerant of poor water conditions and high nitrates. In a large tank with good water conditions, it will live for 15 years.
It is well known for being territorial in some way; this can be in the form of "guarding" some kind of object in the tank--this could be an ornament, filter, plant bunch or simply an area of the tank--and attacking fish that come near it.
Females are thicker than males; otherwise there are no reliable external sex differences.
Originally described in 1931 by H.M. Smith and placed in the genus Labeo [= "one who has large lips"] under the species epithet bicolor ["two colour"]. In 1998 [Yang & Winterbottom] it was moved to the present genus Epalzeorhynchos [erected by Bleeker, 1855] which contains five species, two of which are the rainbow shark (E. frenatum) and the Flying Fox (E. kalopterus). The genus name derives from the Greek epalzes [= curative] and rhyngchos [= snout].
Some ichthyologists consider this genus to be in the subfamily Labeoninae, others in Cyprininae; there are three tribes (if in Labeoninae) or three subtribes under the tribe Labeonini (if in Cyprininae). Eschmeyer’s Catalog of Fishes (2022) considers Labeoninae as the subfamily.
References:
Kulabtong, S., S. Suksri, C. Nonpayom and Y. Soonthornkit 2014 (30 June) Rediscovery of the critically endangered cyprinid fish Epalzeorhynchos bicolor (Smith, 1931) from West Thailand (Cypriniformes Cyprinidae). Biodiversity Journal v. 5 (no. 2): 371-373.
Yang, J.-X. and R. Winterbottom (1998), "Phylogeny and zoogeography of the cyprinid genus Epalzeorhynchos Bleeker (Cyprinidae: Ostariophysi)," Copeia (1), pp. 48-63.