Guyana Flag Cichlid (Mesonauta guyanae)
A tall, dignified South American cichlid with a bold black shoulder stripe — peaceful enough for a large community yet striking enough to anchor any display.
Will it live with a Guyana Flag Cichlid?
We compare each fish against your guyana flag cichlid on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Banjo Catfish✅ CompatiblePeaceful · 15 cm · Medium care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Bearded Corydoras✅ CompatiblePeaceful · 10 cm · Medium care · 18–24 °C (64–75 °F)
- Compatible on the things that matter: shared water near 24–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Bearded Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Bristlenose Pleco✅ CompatiblePeaceful · 12 cm · Easy care · 23–30 °C (73–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Clown Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Discus✅ CompatiblePeaceful · 20 cm · Hard care · 28–31 °C (82–88 °F)
- Compatible on the things that matter: shared water near 28–30 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Discus in a shoal of 6+ or it gets stressed and nippy.
- Giant Kuhli Loach✅ CompatiblePeaceful · 12 cm · Easy care · 24–30 °C (75–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Leopard Frog Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 25–30 °C (77–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 25–30 °C — no size, zone or temperament conflicts.
- Marbled Hoplo✅ CompatiblePeaceful · 14 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Medusa Pleco✅ CompatiblePeaceful · 12 cm · Medium care · 26–30 °C (79–86 °F)
- Compatible on the things that matter: shared water near 26–30 °C, workable temperaments, and no predator-and-prey size gap.
- Pantanal Corydoras✅ CompatiblePeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pantanal Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Porthole Catfish✅ CompatiblePeaceful · 10 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Rubber Lip Pleco✅ CompatiblePeaceful · 12 cm · Easy care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Snowball Pleco✅ CompatiblePeaceful · 16 cm · Medium care · 24–30 °C (75–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–30 °C — no size, zone or temperament conflicts.
- Spotted Rubbernose Pleco✅ CompatiblePeaceful · 12 cm · Medium care · 20–26 °C (68–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Spotted Talking Catfish✅ CompatiblePeaceful · 15 cm · Easy care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Striped Eel Loach✅ CompatiblePeaceful · 12 cm · Medium care · 24–28 °C (75–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Upside-down Catfish✅ CompatiblePeaceful · 10 cm · Easy care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Weather Loach✅ CompatiblePeaceful · 25 cm · Easy care · 5–24 °C (41–75 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–24 °C — no size, zone or temperament conflicts.
- Zebra Pleco✅ CompatiblePeaceful · 10 cm · Hard care · 26–30 °C (79–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 26–30 °C — no size, zone or temperament conflicts.
- Angelfish⚠️ With cautionSemi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Blood Parrot Cichlid⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 24–28 °C (75–82 °F)
- Guyana Flag Cichlid and Blood Parrot Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
- Blue Flash Cichlid⚠️ With cautionSemi-aggressive · 15 cm · Medium care · 24–28 °C (75–82 °F)
- Guyana Flag Cichlid and Blue Flash Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 200 L tank is below the ~210 L this pairing really wants — crowding raises aggression.
- Clown Barb⚠️ With cautionSemi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Clown Barb is a notorious fin-nipper — even though Guyana Flag Cichlid is larger, an active shoal will harass its trailing fins. Only safe in a full group of 6+ with plenty of cover.
- Keep Clown Barb in a shoal of 6+ or it gets stressed and nippy.
- Denison Barb⚠️ With cautionPeaceful · 15 cm · Medium care · 18–25 °C (64–77 °F)
- Expect Guyana Flag Cichlid to harass Denison Barb at times; give dense cover and watch them at feeding.
- Keep Denison Barb in a shoal of 6+ or it gets stressed and nippy.
- Electric Blue Acara⚠️ With cautionSemi-aggressive · 16 cm · Medium care · 22–28 °C (72–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Electric Blue Hap⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 24–28 °C (75–82 °F)
- pH preferences only just meet (Guyana Flag Cichlid 5.5–7.5 vs Electric Blue Hap 7.8–8.5) — target the overlap and acclimate slowly.
- Guyana Flag Cichlid and Electric Blue Hap can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 200 L tank is below the ~250 L this pairing really wants — crowding raises aggression.
- Emperor Peacock Cichlid⚠️ With cautionSemi-aggressive · 16 cm · Medium care · 24–28 °C (75–82 °F)
- pH preferences only just meet (Guyana Flag Cichlid 5.5–7.5 vs Emperor Peacock Cichlid 7.6–8.6) — target the overlap and acclimate slowly.
- Guyana Flag Cichlid and Emperor Peacock Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 200 L tank is below the ~210 L this pairing really wants — crowding raises aggression.
- Fire Blue Empress Cichlid⚠️ With cautionSemi-aggressive · 18 cm · Medium care · 24–28 °C (75–82 °F)
- Guyana Flag Cichlid and Fire Blue Empress Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 200 L tank is below the ~400 L this pairing really wants — crowding raises aggression.
- Goldie Pleco⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 24–29 °C (75–84 °F)
- Guyana Flag Cichlid and Goldie Pleco can both be territorial; doable with space and dense planting, but watch for chasing.
- Green Severum⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 23–29 °C (73–84 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Your 200 L tank is below the ~208 L this pairing really wants — crowding raises aggression.
- Honeycomb Pleco⚠️ With cautionSemi-aggressive · 21 cm · Medium care · 24–29 °C (75–84 °F)
- Guyana Flag Cichlid and Honeycomb Pleco can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 200 L tank is below the ~280 L this pairing really wants — crowding raises aggression.
- Platinum Acara⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 23–28 °C (73–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Spanner Barb⚠️ With cautionSemi-aggressive · 18 cm · Medium care · 23–29 °C (73–84 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Your 200 L tank is below the ~208 L this pairing really wants — crowding raises aggression.
- Keep Spanner Barb in a shoal of 6+ or it gets stressed and nippy.
- Striped Raphael Catfish⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 24–28 °C (75–82 °F)
- Guyana Flag Cichlid and Striped Raphael Catfish can both be territorial; doable with space and dense planting, but watch for chasing.
- Tiger Loach⚠️ With cautionSemi-aggressive · 20 cm · Medium care · 23–27 °C (73–81 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Two assertive fish, one genuinely aggressive: Guyana Flag Cichlid and Alligator Gar will hold territory and clash.
- Alligator Gar (250 cm) is big enough to swallow the 18 cm Guyana Flag Cichlid whole.
- Your 200 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Guyana Flag Cichlid and Clown Knifefish are both territorial and at least one is outright aggressive — expect serious fighting.
- Size gap is too large (90 vs 18 cm): Clown Knifefish will treat Guyana Flag Cichlid as food.
- Your 200 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Size gap is too large (100 vs 18 cm): Fire Eel will treat Guyana Flag Cichlid as food.
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Your 200 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Koi (90 cm) is big enough to swallow the 18 cm Guyana Flag Cichlid whole.
- Your 200 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Two assertive fish, one genuinely aggressive: Guyana Flag Cichlid and Redtail Catfish will hold territory and clash.
- Guyana Flag Cichlid is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
- Your 200 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Two assertive fish, one genuinely aggressive: Guyana Flag Cichlid and Spotted Gar will hold territory and clash.
- Guyana Flag Cichlid is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Your 200 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Two assertive fish, one genuinely aggressive: Guyana Flag Cichlid and Wels Catfish will hold territory and clash.
- Wels Catfish (300 cm) is big enough to swallow the 18 cm Guyana Flag Cichlid whole.
- Your 200 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Guyana Flag Cichlid and Wolf Cichlid are both territorial and at least one is outright aggressive — expect serious fighting.
- Wolf Cichlid (72 cm) is big enough to swallow the 18 cm Guyana Flag Cichlid whole.
- Your 200 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Guyana Flag Cichlid care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 18 cm (7.1 in)
- Min tank size
- 200 L (52.8 gal)
- Temperature
- 24–30 °C (75–86 °F)
- pH
- 5.5–7.5
- Hardness
- 1–12 dGH
- Lifespan
- 8–12 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- Best alone or in a pair
- Family
- Cichlidae
- Origin
- South America — Guiana Shield rivers of Guyana and surrounding lowland drainages
What is a Guyana Flag Cichlid?
The Guyana flag cichlid (Mesonauta guyanae) is a tall, laterally compressed South American cichlid belonging to the family Cichlidae. Adults reach up to 18 cm (7 in) and are instantly recognisable by the bold black diagonal stripe that sweeps from the snout up through the base of the dorsal fin — the “flag” mark that names the entire Mesonauta genus. A secondary dark spot sits at the caudal peduncle, and the overall body is silver-green with a subtle iridescence that shifts under aquarium lighting.
What sets this cichlid apart from many of its relatives is temperament: rated semi-aggressive rather than outright belligerent, it can hold its own against boisterous tank-mates without turning a community tank into a war zone. With a lifespan of 8–12 years under good care, a Guyana flag cichlid is a genuine long-term commitment and a rewarding one. Its dignified, upright posture and strong patterning give it a presence that smaller fish simply cannot match.
Where does the Guyana Flag Cichlid come from?
Mesonauta guyanae is native to the Guiana Shield — an ancient geological formation that gives rise to the rivers flowing through Guyana and the surrounding lowland drainages of northeastern South America. These are predominantly blackwater and clearwater systems: rivers stained amber by decaying leaf litter, with very low mineral content, warm temperatures and gentle flow.
The Guiana Shield is one of the oldest and most biodiverse freshwater regions on Earth. Its fish fauna evolved in relative isolation, which is part of why M. guyanae differs subtly from its better-known cousin M. festivus of the broader Amazon and Orinoco basins. In the wild, flag cichlids are found among submerged vegetation, root tangles and driftwood in the mid-water column — a habitat directly worth replicating in the aquarium.
What size tank does a Guyana Flag Cichlid need?
The minimum practical tank for a single specimen is 200 L (55 gal), and that is genuinely a minimum. A fish that can reach 18 cm (7 in) needs horizontal swimming room, and the semi-aggressive temperament means it needs enough territory that any tank-mates can establish their own space without constant friction.
A bonded pair or a small group with dither fish warrants at least 300–400 L (80–105 gal). Prioritise footprint over height: a longer tank gives more horizontal territory. That said, the flag cichlid is a middle-column species with a notably tall body, so tanks should be at least 45–50 cm (18–20 in) deep to let it move naturally. Driftwood, broad-leaved plants (Amazon swords, Echinodorus species) and bogwood arches provide the broken sight lines and shelter this species seeks. Robust plants are preferred — delicate stem plants may be uprooted during territory-related digging.
What water parameters does a Guyana Flag Cichlid need?
Reflecting its Guiana Shield origins, this species is comfortable across a wide but warm, soft-leaning range:
- Temperature: 24–30 °C (75–86 °F). The species tolerates the upper end well; avoid sustained temperatures below 24 °C.
- pH: 5.5–7.5. It is most relaxed in slightly acidic to neutral water in line with its blackwater homeland.
- Hardness: 1–12 dGH. Soft water is ideal; moderately hard water is tolerated but avoid calcium-heavy tap water without conditioning.
Stability is more important than hitting precise numbers. Cycle the tank fully before introduction, keep up weekly partial water changes of 25–30%, and use a quality canister or sump filter — this is a large fish producing meaningful waste. Peat filtration or Indian almond leaves can help soften and acidify water naturally while adding tannins that replicate the blackwater environment.
What does a Guyana Flag Cichlid eat?
Mesonauta guyanae is an omnivore, and a varied diet is the fastest route to good colour and condition. In the wild the genus feeds on invertebrates, small fish, plant matter and organic detritus — a mixed picture that translates well to the aquarium.
A high-quality cichlid pellet or stick forms the staple. Rotate in frozen or live foods for enrichment: bloodworms, earthworms, krill, chopped prawns and occasional brine shrimp are all accepted eagerly. Including some plant-based foods — spirulina wafers, blanched spinach or cucumber — rounds out the diet and supports immune health. Feed once or twice daily, only what the fish consumes in a few minutes, and fast one day per week to prevent the digestive issues large cichlids can develop from overfeeding.
How does the Guyana Flag Cichlid behave — and what are suitable tank mates?
The Guyana flag cichlid has a semi-aggressive temperament that is better described as assertive than destructive. It will defend a loose territory and may chase fish that venture too close, but it does not typically pursue and harm tank-mates the way highly aggressive cichlids do — provided the tank is large enough and companions are well-chosen.
Suitable companions are robust mid-to-large fish that will not be swallowed. Bleeding-heart tetras, silver dollars, larger barbs, severums and peaceful catfish such as eartheaters or large Corydoras are commonly recommended. Dither fish — active schooling species swimming confidently in the open — are particularly valuable because their calm movement signals safety and reduces the flag cichlid’s wariness. Avoid nano tetras, small rasboras or any fish small enough to fit in its mouth. Highly aggressive cichlids and obvious fin-nippers are also poor choices.
See Guyana Flag Cichlid tank mates for a full, filterable list of compatible species and specific pairing guidance.
How do you tell male from female Guyana Flag Cichlids apart?
Sexual dimorphism in Mesonauta guyanae is present but subtle, especially in juveniles. Adult males tend to be noticeably larger overall and develop longer, more distinctly pointed tips on the dorsal and anal fins — the extensions that give mature males a particularly elegant silhouette. Females generally stay somewhat smaller and are rounder in the abdominal region when in spawning condition or carrying eggs.
Because sexing juveniles is difficult, the most reliable approach when buying is to acquire a small group of four to six young fish and allow natural pairing to occur as they mature. The pair bond, once formed, is usually stable and the pair will cooperate closely during breeding activity.
How do Guyana Flag Cichlids breed?
Breeding M. guyanae is rated hard and is not a casual undertaking. The species is a substrate spawner: the pair selects a flat stone, broad leaf or patch of cleaned substrate, and the female deposits eggs in rows while the male follows to fertilise them. Both parents guard the spawn actively and will become significantly more territorial during this period — tank-mates that were previously tolerated may need to be moved.
Spawning is more reliably triggered after a conditioning period of rich live and frozen foods, a modest temperature increase toward the upper end of the 24–30 °C range, and a water change with slightly softer, more acidic water to mimic the onset of the rainy season. Fry are guarded by both parents after hatching and become free-swimming within a week or so. First foods are microworms, freshly hatched brine shrimp nauplii and finely crushed flake. The difficulty rating reflects the challenge of managing parental aggression in a community setting and successfully raising fry without a dedicated breeding tank.
What diseases are common in Guyana Flag Cichlids?
Large cichlids kept in well-maintained, adequately sized aquaria are generally hardy. The most common problems trace directly to water quality or stress:
Ich (white spot): Pinhead-sized white spots across the body and fins, caused by Ichthyophthirius multifiliis. Typically triggered by chilling or sudden temperature drops — keep temperature stable and avoid draughts near the tank.
Hole-in-the-head (HITH): Pitting or erosion around the lateral line and head area, associated with chronic stress, poor water quality and dietary deficiency. Prevention centres on large, regular water changes, a varied diet and avoiding overcrowding.
Bacterial infections and fin damage: Secondary bacterial infections can follow physical damage from tank-mate aggression or rough handling. Ensure tank-mates are appropriate in size and temperament, and quarantine any new fish before introduction.
Internal parasites: Wild-caught specimens or those from unknown sources may carry internal worms. A prophylactic treatment course in a dedicated quarantine tank is wise before adding new fish to an established community.
Health note: disease diagnosis and medication dosing are beyond the scope of a care profile. If your fish show symptoms, cross-reference against a reputable veterinary or fish-health resource before treating, and always quarantine new arrivals for a minimum of two to four weeks.
How long do Guyana Flag Cichlids live?
In good conditions Mesonauta guyanae lives 8–12 years — an impressive span that puts it in the same category as other long-lived South American cichlids. That longevity is a key consideration before purchase: this is not a fish to acquire on impulse and rehome in a year. It will reward consistent, attentive husbandry with years of bold, characterful display at the centre of a large planted aquarium. Get the tank size and water quality right from the start, feed a varied diet, and choose compatible companions, and a decade of ownership is entirely realistic.
Frequently asked questions
Is the Guyana flag cichlid safe with small fish like tetras?
With caution: it rarely targets fish it cannot swallow but will eat very small species (nano tetras, small rasboras). Mid-sized dither fish such as bleeding-heart tetras or silver dollars are safer choices, and their presence actually calms the flag cichlid's temperament.
How is Mesonauta guyanae different from Mesonauta festivus?
They are closely related and look similar, but guyanae comes from the Guiana Shield drainages of Guyana while festivus is broadly distributed across the Amazon and Orinoco basins. Guyanae also tends to be slightly deeper-bodied. In the trade both are often sold interchangeably as 'flag cichlid', so species-level accuracy requires knowing the source.
What you need to keep a guyana flag cichlid
The baseline is a heated, filtered 200 L+ tank: a reliable heater to hold 24–30 °C (75–86 °F), a gentle filter that won't batter a guyana flag cichlid in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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