Shy and Peaceful: Meet the Keyhole Cichlid

The keyhole cichlid (Cleithracara maronii) is a tropical freshwater fish with an interesting keyhole-shaped marking and a gentle personality that makes it the perfect addition to a home aquarium.

This easy-to-care-for species tolerates a range of water conditions and eats just about anything.

Its main requirement is an environment with plenty of hiding spaces to accommodate its shy nature.

Cleithracara maronii commonly known as keyhole cichlid swimming in a densely planted aquarium


At a Glance

Tank Size: 20 gallons minimum tank size
Group Size: 6 to 8 (minimum of 2)
Water Temperature: 72 – 80°F (22 to 26.6°C)
pH: 6.0 – 8.0
Hardness: 12 – 30 dGH
Lifespan: 7 to 10 years
Breeding: Egg spawning
Adult Size: 4 to 4.75 inches (10 to 12 cm)
Usual Place in the Tank: Middle

Natural Habitat

The keyhole cichlid is a tropical fish. Its natural populations inhabit the lower Orinoco River Basin of Venezuela in South America.

They can also be found in the Barima River of Guyana and the Ouanary River of French Guiana.

The waters of these rivers are slow-moving and heavily vegetated.

Decaying leaves, branches, and fruit in the rivers leads to tinted waters and low pH levels.

Appearance and Biology

Pair of keyhole cichlids swimming together in aquarium

The keyhole cichlid features more subdued coloration as opposed to other cichlids.

Its body color ranges from a light yellow/cream color to light tan/brown.

Over the head and eye, there is a wide, black, vertical stripe.

The distinguishing feature of the keyhole cichlid is a black spot located just behind the midline of the body.

This spot can extend downward in mature fish, creating a unique “keyhole” shape.

Keyholes have a more oval body shape compared with other cichlids.

Their rayed dorsal and anal fins feature long extensions that sweep backward over the rounded tail fin.

Gender Differences

Although it is difficult to tell a male keyhole cichlid from a female, there are some subtle differences.

Males will tend to be slightly larger as adults, and their dorsal and anal fins will have longer extensions.


The keyhole is a small cichlid. As an adult, they reach an average of 4 to 4.9 inches (10 to 12.5 cm).


There is plenty of time for you and your keyhole cichlid to bond as this long-lived species will be a part of your aquarium for seven to ten years.

As with any fish, a proper diet and a well-maintained tank greatly impact your fish’s longevity.


If you are looking for an even-tempered, peaceful cichlid, the keyhole is the fish.

They can be on the shy side, preferring to swim in the middle areas of the tank and around any plants or decorations. They are not known to burrow or tear up live aquarium plants.

The only time you may see some aggression from your keyhole cichlid is when breeding. Males will often attempt to chase off others to form their territory.

To prevent aggression, make sure your tank is large enough, with plenty of areas for your fish to hide.

This species exhibits additional interesting behaviors. First, keyhole cichlids form monogamous breeding pairs. This is important to remember if you plan to breed your fish.

Second, these fish have a unique protective behavior. They startle easily and when they are fearful, they can camouflage themselves. In these cases, they change color to blend into their surroundings.

How many per gallon?

Cichlids are fish for which the typical rule of thumb of “a gallon of water for every inch of fish” does not apply.

These fish need room to swim. While two keyhole cichlids can be kept in a 20-gallon (76 liter) tank, this should be considered the maximum number of fish. Plan on adding at least 10 gallons for each additional fish.

Tank Setup

Tank setup is not too difficult for the keyhole cichlid. As usual, your goal is to create an environment that resembles the fish’s natural habitat.


In the wild, this fish is accustomed to having plenty of plant life, driftwood, and rocks to use as hiding places.

For your keyhole cichlid to feel safe, make sure you have enough of these in your tank.

The sky’s the limit when it comes to decorations in your tank. Basically, anything the fish can swim around and use as shelter will do.

Feel free to add live plants as this fish does not dig in the substrate or nibble on plants.

A fine-grained or sandy substrate is suitable to replicate the fish’s natural environment.

Add some flat stones if you intend to breed your fish as they will use them for spawning.

Water Conditions

As we mentioned, these are tropical fish. Installing a heater may help keep the water temperature regular, especially for smaller tanks.

Keep the water temperature between 72 to 79 degrees Fahrenheit (22 to 26 degrees C).

Although wild keyhole cichlids are accustomed to very low pH levels, those bred for sale are used to typical pH ranges suitable for most aquarium fish.

Keep your tank’s pH between 6.0 and 8.0. The water hardness should be between 12 to 30 dGH.

Clean your tank regularly, including the substrate.

Replace a portion of the water regularly to avoid the buildup of nitrates/nitrites and ammonia.


Remember that the keyhole cichlid prefers slower-moving waters. Installing a quality filter with an adjustable water flow will ensure that there is not a strong current.

Make sure your tank has a well-fitting cover, as the keyhole cichlid can jump out if frightened.

The lighting should be adjustable and kept dimmed as your fish is used to lower light conditions. Floating plants may also help to provide the necessary shade.

Tank Mates

Cleithracara maronii known as Keyhole cichlid swimming in community aquarium with a neon tetra and plecostomus

Due to the natural shyness of the keyhole cichlid, this is not a species that should be kept alone. When kept on their own, these fish will be highly stressed, shy, and more prone to illness.

You will find that a well thought out community tank, including non-aggressive dither fish, will help encourage more comfort and natural activity.

In larger tanks, consider the following to pair with your keyhole cichlid:

Avoid the following:

  • Smaller fish, such as tetras, that your keyhole cichlid may think is food

Remember that the keyhole cichlid can show aggression when establishing territory in preparation for breeding. To reduce this, make sure your tank is large and has plenty of areas for your fish to hide.

Food and Diet

Keyhole cichlid is eating a pellet at the tank's bottom

The keyhole cichlid is an omnivore and will pretty much eat whatever you throw in the tank.

That said, you should ensure that your offerings provide a well-balanced diet to keep your fish healthy.

Start with high-quality flake food or cichlid pellet. In addition, your fish will happily eat:

  • Live, dried, or frozen foods
  • Daphnia
  • Artemia
  • Bloodworms
  • Larvae
  • Insects
  • Beetles
  • Brine shrimp
  • Vegetables, such as blanched peas or zucchini.

Ideally, feed your fish small portions two to five times a day. Realistically, you can provide a larger meal one to two times daily.

Ensure the food is the proper size for your fish’s mouth.


We have already recommended keeping a group of six to eight fish and allowing them to form monogamous pairs.

After seeing the fish pair up, a separate breeding tank may be best if your fish are part of a community tank.

This can help prevent your fish from eating their young if they feel threatened by other fish in the tank.

Breeding Behavior

There are no specific triggers required for your keyhole cichlids to spawn.

Ensure your tank has flat stones, broad-leafed plants, or a smooth glass bottom for breeding.

The female keyhole cichlid will deposit up to 300 eggs, which will stick to these surfaces.

The female will remain close to the eggs and guard them. The male will defend the territory.

Caring for the Fry

The eggs will hatch in three to five days, and the fry will be free-swimming a few days after that.

At that time, you can feed the fry infusoria or newly hatched brine shrimp.

The parents will continue to care for the young fish for several weeks up to six months after they hatch.

Be aware that young keyhole cichlid pairs may be unsuccessful in their preliminary breeding attempts. In these cases, they may eat the eggs or young.

If this happens, do not worry. They will typically have success with subsequent attempts.


The keyhole cichlid is a very hardy species that can tolerate a wide range of tank conditions.

As such, they are not prone to any specific diseases.

It is always important to ensure water quality and tank conditions are consistent and within the fish’s tolerance ranges.

In addition, make sure your fish eats a well-rounded diet to be as healthy as possible.

Frequently Asked Questions

1. How big do keyhole cichlids get?

Keyhole cichlids are a small cichlid species.As an adult, they reach an average of 4 to 4.75 inches (10 to 12 cm).

When you purchase them, they may be at a smaller size of one to 1.5 inches (2.5 to 4 cm).

2. Are keyhole cichlids aggressive?

Not typically. They are peaceful both with members of their own species and with similarly sized and tempered fish.

The only time they show aggression is when breeding. Males can squabble when defending territory or their young.

3. What do keyhole cichlids eat?

Whatever you throw in the tank. That may be a bit of an exaggeration, but the keyhole cichlid is not a fussy eater.

Start with a base of quality flake food or cichlid pellets, then supplement with live or frozen foods and some vegetables.

Final Recommendations

Overall, the keyhole cichlid is a wonderful addition to your home aquarium.

Kept in pairs in a species-only tank or as part of a community tank, their gentle, almost shy nature allows them to live with other similarly sized and tempered species.

Although not as brightly colored as other cichlid types, this long-lived fish is more peaceful and a bit smaller, resulting in reduced tank size requirements.

You can purchase keyhole cichlids online for anywhere from around $9 to $13.

They will require a decent filter system with an adjustable flow rate, lower lighting, and a heater to maintain water temperature.

Tell us your experiences with keeping a keyhole cichlid!

What decorations or plant types do your cichlids like best?