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Chromides and Pearlspots: Beautiful Asian Cichlids
Comparatively few cichlids are native to Asia, and all of these are confined to one of two distinct areas, westernmost Asia between Israel and Iran on the one hand and the southern tip of the Indian subcontinent in the south. There are no cichlids native to any other parts of Asia, though African species, particularly tilapias, have become established across much of tropical Asia in the last few decades.
The West Asian species are virtually never traded, but the three species from India and Sri Lanka have become hobby staples. Known collectively as 'Chromides', these three Etroplus species are among the most primitive cichlids known, and in many ways are probably very similar to what the first cichlids were like when they evolved some 50 million years ago. Oddly enough they are not closely related to the West Asian cichlids; their closest living relatives are among the Madagascan cichlids, in particular those cichlids placed in the genus Paraetrolpus. Some ichthyologists place them all in a subfamily within the cichlids known as the Etroplinae.
The three Etroplus species are the Orange Chromide Etroplus maculatus, the Green Chromide Etroplus suratensis, and the Canara Pearlspot Etroplus canarensis. Of these, Etroplus maculatus and Etroplus canarensis are both comparatively small fish, getting to maximum lengths of about 8 cm and 12 cm respectively; Etroplus suratensis is rather bigger, typically reaching lengths of between 20-40 cm when fully grown.
Orange Chromides occur on both the southern tip of India and the island of Sri Lanka. It is normally found in coastal freshwater habitats but also occurs in estuaries and brackish water lagoons. The Green Chromide is found in the same parts of India and Sri Lanka, but is more strongly associated with brackish water than the Orange Chromide and is usually found in in estuaries, river mouths and lagoons.
The Canara Pearlspot is distinct from the other two Etroplus species in that it is a strictly freshwater species only found in a very restricted part of India, southern Karnataka.
Water chemistry and temperature
Of the three Chromides, the Canara Pearlspot is the best candidate for the standard freshwater aquarium. It isn't fussy about water chemistry and will do well in both soft and hard water provided extremes are avoided; aim for 5-15 degrees dH, pH 6.5-7.5. Middling water temperatures will suit it well, 24-26 degrees C being ideal. Because the Canara Pearlspot comes from shallow rivers with plenty of current and oxygen, a robust filtration system is important.
Orange Chromides are found in both freshwater and brackish water habitats in the wild, but under aquarium conditions do consistently better in slightly brackish water. Hard, alkaline water with a specific gravity around SG 1.002-1.005 suits it very well. Under such conditions it is hardy and easy to keep. Again, middling water temperatures are best, though anything between 22-28 C is acceptable.
The Green Chromide is the species most strongly associated with brackish water and it needs saline conditions to do well; aim for a specific gravity between 1.003 and 1.012. Once again, a middling water temperature is recommended.
All the Chromides are omnivores, and in the wild consume both plant and animal foods. But the Orange Chromide and the Canara Pearlspot feed primarily on small prey such as insect larvae and zooplankton, whereas the Green Chromide feeds heavily on soft aquatic plants and filamentous algae. So while all three species will accept a wide range of foods, the precise balance of foods will vary between species.
Algae-based flake foods make excellent staples for all three species, augmented with small live or wet-frozen invertebrates including bloodworms, fortified brine shrimps, daphnia, glassworms and mosquito larvae. Blanched lettuce, cooked spinach and cooked peas can be used to provide the greens. Live plants are generally ignored by the Orange Chromide and Canara Pearlspot, but the Green Chromide may consume soft aquatic plants given the chance.
None of these fish is particularly predatory, but all will eat livebearer fry and any other tankmates small enough to swallow whole.
The Green Chromide and the Canara Pearlspot are both sociable, schooling fish best kept in groups of six or more specimens. Both get along extremely well with peaceful tankmates of similar size. In the case of the Canara Pearlspot that can include freshwater species like tetras, barbs and rasboras, while the Green Chromide will normally be kept with scats, monos, archerfish, sailfin mollies and Colombian shark catfish
The Orange Chromide is peaceful but territorial, and pairs will defend territories with considerable vigour. They are best kept as pairs on their own in brackish water communities alongside such fish as mollies, glassfish, halfbeaks and gobies.
In the wild Orange Chromides and Green Chromides sometimes exhibit a curious symbiosis where the smaller fish act as "cleaners" that remove external parasites and dead skin from the larger fish. Under aquarium conditions the two species cohabit very well.
All three species have been bred in captivity, though only the Orange Chromide is commonly spawned by hobbyists. Pairs spawn on solid surfaces, often inside caves, and both parents defend the nest. The fry hatch after about 5 days, and once the fry are feeding, they consume special mucous from the flanks of the parents, a behaviour most famously associated with Discus. The fry will also take brine shrimp nauplii, microworm, and, eventually, liquid or finely powdered fry food. Orange Chromides make excellent parents and will look after their fry for several weeks.
Orange Chromide Etroplus maculatus
There are two forms of the Orange Chromide available for sale. The most commonly sold form is an artificial bright yellow-orange variety with few or no markings on its flanks. Less often seen is the wild-type that is greenish most of the time but turns orange when spawning, and breeding males are further distinguished by acquiring an expansive region of black that covers the ventral surface. Both males and females bear one or more blotches on the flanks, including a round black eyespot halfway between the eye and the caudal peduncle.
This is a small fish with a maximum length of 8 cm. It is peaceful and works extremely well in community tanks, but mated pairs will be territorial when spawning and can cause problems if the tank is too small. Pairs tolerate other Orange Chromides provided there is adequate space.
Orange Chromides are sometimes sold as freshwater fish and may do well in hard freshwater indefinitely, but like a lot of other species from coastal habitats they are healthier and more colourful if kept in at least slightly brackish conditions. Nonetheless this species is quite easy to keep and suitable for aquarists new to cichlids provided they are prepared to give them the brackish water conditions they prefer.
Green Chromide Etroplus suratensis
Although not often seen in aquarium shops this is one of the prettiest large cichlids and well worth keeping. Adults are green with dark oblique bands on the flanks and hundreds of silvery speckles on their body and fins. Maximum length in the wild is said to be 40 cm but that is very unusual; even in the wild most specimens are only about 20 cm in length and that is the usual size for aquarium specimens as well.
Despite its large size this species is surprisingly peaceful and should be kept in a large group of at least 6 specimens. It tolerates non-aggressive tankmates very well, and generally ignores even quite small tankmates unless they're obviously bite-sized.
Green Chromides need fresh greens in their diet as well as brackish rather than freshwater conditions. Given their large adult size and the need for a big tank with strong filtration, these are fish for advanced aquarists.
Canara Pearlspot Etroplus canarensis
The Canara Pearlspot used to be very rarely seen in aquarium shops but the species is now bred on fish farms and specimens are much less expensive than they once were. Healthy specimens are extremely attractive, but their colouration is difficult to explain and doesn't really show up well in photographs. They are essentially yellowy-brown with dark wedge-shaped markings on their flanks, but their colouration can be very intense and groups are exceptionally eye-catching. At their best these are amongst the most beautiful cichlids in the hobby.
In terms of basic care Canara Pearlspots are fairly adaptable as has been outlined above, and their moderate adult size of around 12 cm means that a group of six specimens will not need a particularly big tank to do well, 250 litres being ample. Like most cichlids they are sensitive to nitrogenous wastes including nitrate, so good filtration and frequent water changes are essential. They can also be easily bullied by more aggressive tankmates, so are best kept with species like rasboras and barbs that can act like dither fish.
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