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Keyhole Cichlid – Cleithracara maronii

Keyhole Cichlid - Cleithracara maronii - Male

Cichlids are a very ancient and extensive classification of fishes dating back millions of years before, for example, dinosaurs. Cichlids probably originated around 550 million years ago (give or take a month or two 😀) and there are somewhere in the region of 2,000 to 3,000 different species, of which around 1,700 have been classified (at the time of writing).

Cichlids can make excellent community fish but you should take care because not all Cichlids are good community fish and may devastate an established aquarium, treating their tankmates as food, so before choosing a Cichlid, please ensure that you know whether or not your choice will be appropriate to your needs.

Is Keyhole Cichlid (Cleithracara maronii) a good community fish? Keyhole Cichlid (Cleithracara maronii) should be considered to be an excellent community fish assuming that the community is one of non-aggressive, non-predatory species. Keyhole Cichlid (Cleithracara maronii) is suitable for all community aquariums although it can be somewhat gently territorial during breeding. 

Key Facts about Keyhole Cichlid (Cleithracara maronii)

CategoryKey Facts
Common name(s)Keyhole Cichlid
Scientific nameCleithracara maronii
Originate fromFrench Guiana and occurs in most river drainages of the country as well as Guyana, Suriname, the Orinoco delta region in Venezuela, in South America and on the island of Trinidad
Care requiredEasy to care for and very beautiful
TemperamentRelatively placid shoaling fish
Colour & FormGourami-shaped body with very elegant finnage
LifespanUp to 10 years
Adult sizeMale is around 4 inches – female is around three inches
DietOmnivorous – eats Daphnia, Bloodworm, Tubifex worms and pellet or flake food in the aquarium.
Aquarium size36 inches in length or greater
Compatible withMost other Tetras, Barbs, Danios, Guppies and other livebearers, dwarf cichlids, smaller Gouramis, catfish and loaches that live in fairly neutral, soft water
Avoid keeping withLarge and/or aggressive species in too small an aquarium and known fin-nippers
BreedingEasy if you put the fish in the right environment.
Water temp76 – 81 Fahrenheit
Water pH4.5 to 7.5
Water hardness (dGH or dH)12 to 30 dGH

Origins of Keyhole Cichlid (Cleithracara maronii)

Keyhole Cichlid (Cleithracara maronii) is endemic to French Guiana and occurs in most river drainages of the country as well as Guyana, Suriname, the Orinoco delta region in Venezuela, in South America and on the island of Trinidad. At the time of writing, Keyhole Cichlid (Cleithracara maronii) is the only known species of the genus, Cleithracara.

It is usually found in nature in slow-flowing, “blackwater” streams, on the margins of larger rivers, in marshland, in ponds and also in lakes but seldom, if ever, in stagnant water.

Basic Characteristics of Keyhole Cichlid (Cleithracara maronii)

Keyhole Cichlid (Cleithracara maronii) will grow up to around 4 inches in length if male and around 3 inches in length if female in the aquarium. In young fish, it is difficult (pretty impossible) to distinguish between the sexes so if you are purchasing young fish then buy half-a-dozen or more and you should have a mix of the sexes. 

The adult male of the species tends to have a more vibrant color than the female. The extended dorsal fin of the Keyhole Cichlid (Cleithracara maronii) has an elongated upper tip at the rear which comes to a point whilst in the female, the tip of the dorsal fin is rounded. The dorsal fin of both male and female are unusual in that in both, the front half of the fin is quite shallow and where the caudal peduncle starts, both male and female dorsal fins then flare into elegantly flowing, elongated fins.

The adult female will also have a visible ovipositor (egg duct) just in front of the anal fin during egg laying.

The lifespan of Keyhole Cichlid (Cleithracara maronii) is around eight to ten years but this can vary enormously depending on tank conditions and general health.

Keyhole Cichlid (Cleithracara maronii) prefers fairly soft, acidic water, often described as “blackwater” with plenty of dissolved tannins, with a pH of 4.0 to 5.0 in nature but in the range of 4.5 to 7.5 in the aquarium (because most are captive-bred) and a temperature range between 76 and 81 degrees Fahrenheit and from 12 to 30 dGH.

Keyhole Cichlid (Cleithracara maronii) enjoys soft to medium, acidic water conditions so it will be comfortable with other species of similar size that prefer this type of water chemistry.

As the Keyhole Cichlid (Cleithracara maronii) has elongated finnage it is advised to avoid keeping them in company with any fin-nippers. Keyhole Cichlid (Cleithracara maronii), being Cichlids, will defend themselves and, especially in respect of smaller fin-nippers, they are likely to retaliate with prejudice.

The Keyhole Cichlid (Cleithracara maronii) get on well with pretty well all other fishes (that are not reputed to be predatory) and, because it has a small mouth, it is unlikely to eat small species, despite its size.

Keyhole Cichlid (Cleithracara maronii) will generally dwell near the bottom of the water column and will enjoy a fine substrate, as it is something of a “sifter” when feeding in that it will take in a mouthful of the substrate and sift out any food, expelling the remaining substrate.

The physical appearance of Keyhole Cichlid (Cleithracara maronii)

Keyhole Cichlid (Cleithracara maronii) has a tall, relatively slim body. It is a slim species in the way that an angelfish is slim, rather it resembles a Gourami in its overall shape. The body is silver-grey in color with a black, marbled scales which is further distinguished by some vertical stripe running up through the eye and curving back to the leading edge of the dorsal fin. The Keyhole Cichlid (Cleithracara maronii) gets its name from the black, keyhole-shaped black vertical stripe just behind its mid-section, roughly in line with the leading edge of the anal fin.

A few more characteristics may be described as follows:

  • There is a horizontal, grey stripe running roughly along the lateral line from behind the gill plates to the rear of the caudal peduncle.
  • The rays of the dorsal fin are somewhat short and spiny until they reach the keyhole and the dorsal fin then becomes much more flamboyant, as it flows backward.
  • All of the fins, to a lesser or greater extent, have golden yellow coloring towards their root and it is a good indicator of good health if the golden color is more pronounced.
  • The caudal fin of the adult male will be longer than that of the female.

The Keyhole Cichlid (Cleithracara maronii) is not a small Cichlid and has extended dorsal and anal fins. The fins of the male can tend to be longer than those of the female. It is advised not to include this species with known fin-nippers.

The living environment for Keyhole Cichlid (Cleithracara maronii)

Keyhole Cichlid (Cleithracara maronii) enjoys being in the shade so a well-planted tank is beneficial to it. In nature, it is most certainly a “blackwater” species.

Keyhole Cichlid (Cleithracara maronii) will appreciate floating leaves and pretty well any broadleaf will assist the condition of the tank, as not only do such leaves provide shade but also, as they decompose, they provide infusoria for any fry in the tank. This also helps adults to determine that breeding conditions are good because they will appreciate the fact that there is a ready source of food for newly-hatched fry.

Note that Keyhole Cichlid (Cleithracara maronii) will generally mate for life and, being biparental, they will make good parents for any brood that they are rearing.

It is recommended that Keyhole Cichlid (Cleithracara maronii) are kept as a small shoal. The male, in particular, can be gently territorial but setting up the tank so that sightlines are broken up will mitigate the risks of territorial behavior in general. 

When purchasing Keyhole Cichlid (Cleithracara maronii) it is generally recommended to buy around six fish. It may be impossible to sex the fish when purchasing them as immature specimens but, in due course, they will find their own mate and are, from that point, generally both monogamous and biparental.

Having a clear, broad area of a fine substrate will protect the elegant finnage of your Keyhole Cichlid (Cleithracara maronii).

Overall, Keyhole Cichlid (Cleithracara maronii) are the most attractive and most elegant addition to your aquarium.

The diet of Keyhole Cichlid (Cleithracara maronii)

Keyhole Cichlid (Cleithracara maronii) is primarily omnivorous but has a preference for live food, feeding on a range of invertebrates in nature. In the aquarium a diet of live or frozen Artemia, Bloodworm and Daphnia is recommended and Keyhole Cichlid (Cleithracara maronii)  will readily eat pelleted food and flake food. That said, they prefer to stay close to the bottom of the water column and sift through the substrate for their food. For this reason, a fine substrate is recommended.

Sexual differences in Keyhole Cichlid (Cleithracara maronii)

It is reasonably easy to distinguish the sex of the adult Keyhole Cichlid (Cleithracara maronii) because the adult male is significantly larger and has a deeper color, especially at breeding times. The rear of the male’s dorsal fin is more extended and pointed than that of the female and his caudal fin is also longer. The female is also fuller-bodied when viewed from above, especially when carrying eggs (gravid). The female has a visible ovipositor (egg duct) just in front of the anal fin.

Keyhole Cichlid - Cleithracara maronii - Male
Keyhole Cichlid – Cleithracara maronii – Male
Keyhole Cichlid - Cleithracara maroni - Female
Keyhole Cichlid – Cleithracara maronii – Female
Keyhole Cichlid - Cleithracara maronii - Pair
Keyhole Cichlid – Cleithracara maronii – Pair

Aquarium size for Keyhole Cichlid (Cleithracara maronii) 

It is generally advised that the minimum tank size for Keyhole Cichlid (Cleithracara maronii) should be one of at least 36 inches in length or more due to the fact that a shoal of around six per species should be maintained and the adult fish will be around four inches or more in length. This will enable your small shoal to move around freely. A smaller tank will be too restrictive (unless it is a breeding tank) and the fish will suffer as a result whilst a larger tank is always to be recommended.

In a community tank, including some floating Java Moss will give smaller fish and any fry a safe haven from larger or more vigorous species and it certainly helps to break up the sightlines in the aquarium.

There is a predominance of so-called “Nano tanks” available but, being old-fashioned, I prefer my fishes to live in an environment which, at least, attempts to mimic nature, rather than living in what I would liken to a piscine prison cell. The tank should be well-planted but with clear areas where the fish can swim freely. The water should have a certain amount of movement, as Keyhole Cichlid (Cleithracara maronii) enjoy a flow of water.

Keyhole Cichlid (Cleithracara maronii) – Videos

Caring for Keyhole Cichlid (Cleithracara maronii) – Videos

Breeding Keyhole Cichlid (Cleithracara maronii) – Videos

Are you keeping tropical fish as a hobbyist or as a breeder?

This is a question too often ignored in my humble opinion. If you are a breeder (either commercially or as a hobbyist who gives away young fish to other hobbyists) then you will need the resources to move fish into breeding tanks in order to maximize the yield of fry that will grow up either for sale or to give them away.

If you are keeping fish for the joy of observing them in something resembling a natural habitat then you may feel that it is appropriate to allow nature to take its course and, as and when different species breed, then many of the eggs (and surviving fry) will be eaten either by their parents or by other fish in your aquarium. This is the natural order of things because this is what will happen in nature. The fittest may well survive to reach adulthood.

Ultimately, the choice is yours to make.

How do Keyhole Cichlid (Cleithracara maronii) breed?

In total, the female Keyhole Cichlid (Cleithracara maronii) could lay up to 300 to 400 eggs during a single spawning. 

Keyhole Cichlid (Cleithracara maronii)  eggs will hatch in around three to five days and the fry will become free-swimming after around a further three to five days.

It is generally true that Keyhole Cichlid (Cleithracara maronii) make good parents and will not prey on their own young. In general, the male will protect the territory whilst the female will tend to care for the eggs and fry but these roles are interchangeable.

Keyhole Cichlid (Cleithracara maronii) will guard their brood for up to six months to ensure a good survival rate.

Keyhole Cichlid (Cleithracara maronii) have an elaborate courtship ritual and, once they have formed a monogamous pair they may spend up to ten days preparing a suitable site to spawn. A terractotta plant pot on its side in a secluded area of the aquarium will provide an ideal site for the pair to spawn.

The female Keyhole Cichlid (Cleithracara maronii) will generally lay her eggs in a line along a flat surface. The male will then swim over the eggs and fertilize them. This process will then be repeated until the female has laid all of her eggs and the male has fertilized then and the result will be several rows of fertilized eggs.

The female will tend to stay close to the eggs, fanning water over them which will remove and unfertilized eggs and thus protect the rest from the risk of fungus.

The male will provide “overwatch” around the broader area, gently warding off potential predators.

The Keyhole Cichlid (Cleithracara maronii) takes responsibility for post-spawning care and may become aggressive if it feels that the brood is threatened. For this reason, if possible, a breeding tank is recommended.

If Keyhole Cichlid (Cleithracara maronii) feels threatened, it will tend to take on a much darker body color and will find shelter in plants or under rocks but it will defend its brood.

In a well-planted aquarium with floating Java Moss, the Cichlid will often spawn in the community tank and at least some of the fittest fry will survive to adulthood by hiding in the Java Moss.

In a breeding tank, it is always a good idea to include a few aquatic shrimp, as they will consume any unfertilized or dead eggs but won’t tend to predate on viable eggs.

Breeding tank for Keyhole Cichlid (Cleithracara maronii)

You should prepare a tank of around twenty gallons in size with mature, soft, flowing water. The water should have a low level of light and broad-leaved plants together with some well-cleaned slate inserted flat upon which the female will lay her adhesive eggs. A terracotta plant pot laid flat is also a perfect spawning site. 

It is recommended that the substrate consists of a fine substrate (sand) without sharp edges. 

Arrange your tank heating so that you can slowly remove up to half of the tank water and then replace it with collected rainwater (very slightly cooler than the aquarium water – but not so much that White Spot could result) and repeat this daily until the Cichlids spawn. This water and temperature change will encourage spawning, as it mimics nature. The rainwater is most important though some argue that tap water is fine.

Cichlids prefer to spawn where the water is flowing so a decent pump is required to synthesize that flow.

Feed up your Cichlids on bloodworm, which will sink to the bottom and burrow into the substrate. Your Cichlid will love rooting out the bloodworm and it can help to trigger spawning.

You may also wish to introduce baby brine shrimp, mosquito larvae or tubifex worms as an inducement to reproduction and live food will be very much appreciated. This will also tend to divert the attention of the Keyhole Cichlid (Cleithracara maronii) from preying on their own eggs and fry though cannibalism is not characteristic of Keyhole Cichlid (Cleithracara maronii).

Reduce the water movement by turning down the pump once the eggs are laid – only regular aeration is now required. Keep the lights off (or very low) and the tank dark (of fairly dark)  because eggs and fry can be particularly sensitive to the light.

The eggs will hatch typically in three to five days depending on tank temperature and conditions and the fry will become free-swimming after around three to five days after hatching. 

Keep the tank more-or-less unlit for the first week or so then gradually increase the lighting. Bear in mind that the eggs and fry of a fish as small as the Cichlid will be tiny indeed so you may need to use a magnifier “app” on your smartphone or a macro lens to see anything at all. A collection of eggs is generally easy to spot, as they look like a collection of tiny pearls.

The newly hatched fry will feed firstly on their yolk sac and remain static but, once free-swimming, can be fed infusoria and will also thrive on egg yolk during the first two to four weeks. 

Once the fry are free-swimming and their yolk sacs are depleted, then add baby brine shrimp and/or white worms. Once the fry are sufficient in size not to be treated as a snack then they can be introduced into the community tank where they will join the existing shoal. Before moving the adolescent fish into the community tank ensure that you have balanced the water temperatures to mitigate the risk of White Spot or other diseases being triggered.

Unless you are breeding commercially, you may wish to consider moving the fry into the community tank sooner rather than later. It may seem harsh but the adult fish in the tank will deal with any fry that are unlikely to survive to adulthood in the wild and you are synthesizing, to the best of your ability, a wild environment. The fittest fry will probably survive whilst the rest will be dealt with by the community.

Should your Keyhole Cichlid (Cleithracara maronii) have a special diet for breeding?

Adult Cichlids don’t need any particular inducement to breed. That said, it has been suggested that adding tubifex, bloodworm, or mosquito larva may encourage them, presumably because the addition of a new food may “fool” the fish into thinking that it is breeding time. From my own experience, I would always recommend keeping all of your fish in the best possible condition at all times, as this is good for the wellbeing of your fish.

Mike Wheeler

I started keeping freshwater tropical fish in 1972 and it has been something of a passion ever since. In this website, my aim is to build up an everyman's guide to help the everyday aquarist get the best from this inspiring and entertaining hobby.

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