Asia isn't the first place you'd look for cichlids, but the Orange and Green Chromide are two of the family's most fascinating oddities, with unusual habitats, remarkable family lives and a surprising relationship between them.
When you think about cichlids, you might picture small dwarf species, like Apistogramma, lurking in blackwater streams, the colourful, active Tropheus of Lake Tanganyika, or perhaps your mind goes to Central America, to species like the firemouth cichlid.
And there’s a reason for that. There aren’t many cichlids that live in Asia, but those that are there are certainly fascinating. Today, we’re going to look closely at two species whose native distributions are far from the weirdest thing about them.
Meet the Chromides
Those two fish are the orange chromide and the green chromide. Both are native to South Asia, occurring in India and Sri Lanka and, until 2014, both belonged to the genus Etroplus. The green chromide remains in this genus, known as Etroplus suratensis, but the orange chromide has been placed in the resurrected genus Pseudetroplus, where it is currently the only recognised species.
What's fascinating is, both of these fish are euryhaline, occurring in estuaries and coastal lagoons where salinity can fluctuate considerably, and they are capable of moving between freshwater and brackish conditions. Tolerance of changing salinity is unusual among cichlids, and it is one of the things that makes chromides such fascinating fish.
Etroplus canarensis is another relative, although this species is truly a freshwater cichlid.
All photos by Shutterstock unless otherwise stated
Orange Chromide (Pseudetroplus maculatus)
The orange chromide is the smaller of the two species, reaching around 9.5cm (3.7"). In nature they are rather opportunistic feeders, eating algae and plant matter alongside fish eggs and small invertebrates.
There are two forms of orange chromides occasionally found in the hobby. The natural fish has more subtle orange hues with a prominent black spot (pictured above), the aquarium variant is a solid orange with tiny red spots (pictured below).
Exporters sometimes label the natural-coloured fish as a ‘green chromide’, which can cause confusion. Always check the scientific name before ordering, as the true green chromide is a completely different — and much larger — species.
Orange Chromide Fact File
Scientific name: Pseudetroplus maculatus
Size: Can reach up to 9.5cm (3.7").
Origin: Native to India and Sri Lanka.
Habitat: They live in a range of habitats including coastal lagoons, estuaries, rivers, and smaller streams. They can move between freshwater and brackish conditions.
Minimum tank size: 100x40x30cm (39x16x12").
Water requirements: Can be maintained in freshwater or brackish water. Aim for stable conditions with the range of pH 7.2-8.5, and up to 25 dH. If opting for brackish water, aim for a specific gravity between 1.005 and 1.010 s.g.
Temperature: 20-26°C (68-79°F).
Temperament: Gregarious in nature, and best kept in groups. They are peaceful outside of spawning and can be kept alongside peaceful fish that are too large to eat and importantly, tolerate the same water conditions.
Feeding: An unfussy omnivore, offer a variety of flakes, granules, live and frozen foods and ensure some greenery is included.
Availability & cost: Uncommon to find in stores, but available with some effort. Prices vary depending on size, with individuals being available for as little as £8 each.
Green Chromide (Etroplus suratensis)
The green chromide is much larger than its relative. They commonly reach between 20 and 30cm (7.9-12"), although reports suggest their maximum size could be as large as 40cm (16").
Despite being much larger, this species is also gregarious, with shoals looking rather impressive moving through the lagoons and brackish estuaries. Being social fish, they do best in groups of six or more, and that along with their larger size means they are unsuitable for all but the largest of tanks.
The green chromide is not only valued as an ornamental fish for its attractive markings, but is also an important food fish in its native range. Karimeen Pollichathu is a Kerala delicacy, where the "Karimeen" or "pearl spot" – alternative names for Etroplus suratensis – is marinated in spices and wrapped in a banana leaf.
Green Chromide Fact File
Scientific name: Etroplus suratensis
Size: Can reach up to 40cm (16") although they often stay smaller.
Origin: Native to India and Sri Lanka.
Habitat: Primarily lives in brackish water in estuaries and lagoons, although they can move between freshwater and fully marine conditions for brief spells.
Minimum tank size: 180x60x60cm (72x24x24") although larger will be required if they reach their maximum size.
Water requirements: Best maintained in brackish water although they will likely be held in freshwater in shops. Aim for stable conditions with the range of pH 7.5-8.5, 12-30 dH, and between 1.005 and 1.010 s.g.
Temperature: 23-26°C (73-79°F).
Temperament: Gregarious in nature, and best kept in groups. They are peaceful outside of spawning although their large size means smaller tanks mates are unsuitable.
Feeding: An unfussy omnivore, offer a variety of flakes, granules, cichlid pellets, live and frozen foods and ensure some greenery is included.
Availability & cost: Uncommon to find in stores, but available with some effort. Prices vary depending on size, with individuals being available for as little as £8 each.
Photo by Alex Bell
The Cichlid That Cleans Other Cichlids
Perhaps the strangest thing about Chromides is what happens when these two species meet.
The smaller orange chromide has been observed picking parasites from the flanks of the much larger green chromide – a behaviour remarkably similar to that seen between cleaner wrasse and reef fish.
Whether the orange chromide gets much nutritional benefit is less clear, but the green chromides certainly profit from having the parasites removed.
Brilliant Brood Care
Both species are biparental substrate spawners, laying adhesive eggs on flat surfaces which the parents then protect from potential predators. Both parents take part in brood care, taking turns to fan and mouth the eggs.
Once hatched, the fry are moved to small pits dug into the substrate, where they remain until their yolk sacs have been absorbed.
Like discus, the fry have also been observed engaging in micronipping, biting at their parents' flanks and feeding on their mucus. It sounds unusual, but this behaviour provides the developing fry with an additional source of nutrition during their early stages.
Perhaps most remarkable is the length of time the parents remain involved. Orange chromides have been observed guarding their offspring until they are almost adult size — an unusually prolonged period of parental care compared with many other cichlids.
Two cichlids worth discovering
Neither of these chromides are likely to become the next cichlid craze. They are relatively uncommon in the hobby, and the green chromide in particular demands considerably more space than most aquarists can provide.
But that rarity is part of their appeal.
Here are two cichlids from a part of the world that is rarely associated with the family, capable of living in changing salinities, forming strong social bonds and providing unusual parental care. Add in the orange chromide's remarkable cleaning behaviour and the green chromide's importance as a food fish, and these are far more than simply unusual-looking aquarium species.
For aquarists looking for something a little different, the chromides are certainly worth discovering. They might not be the most familiar cichlids in the hobby, but they could be among the most fascinating.