Scrapermouth Mbuna Care Guide: The Algae-Grazing Specialist

Table of Contents

• Key Takeaways
• Species Overview
• Classification
• Origin & Natural Habitat
• Appearance & Identification
• Average Size & Lifespan
• Care Guide
• Tank Mates
• Food & Diet
• Breeding & Reproduction
• Common Health Issues
• Common Mistakes to Avoid
• Where to Buy
• FAQ
• Closing Thoughts

If you want a mbuna that looks like no other fish in your tank, the Scrapermouth Mbuna delivers. Labeotropheus trewavasae has one of the most distinctive facial profiles in the entire cichlid world — a wide, downturned mouth and an enlarged, fleshy nose that looks almost comically oversized. But that unique anatomy isn’t just for show; it’s a highly specialized adaptation for scraping algae from rock surfaces with incredible efficiency.

Beyond the unusual face, the Scrapermouth is a visual treat. This species comes in a wide range of color variants depending on collection location — from classic blue males with dark barring to stunning orange blotch (OB) females. Few mbuna species offer as much variety within a single species.

Fair warning, though — these are robust, territorial fish that demand respect. Males in particular can be quite aggressive, especially during breeding season. If you’re prepared for that challenge, the Scrapermouth Mbuna is a fascinating and rewarding species to keep. Here’s everything you need to know.

Key Takeaways

• Unmistakable appearance — Wide downturned mouth and enlarged fleshy nose; impossible to confuse with any other species
• Multiple color variants — Blue, yellow, orange, OB (orange blotched), and combinations depending on location
• Aggressive and territorial — Males are highly territorial, especially during breeding
• Specialized algae grazer — Mouth structure is perfectly adapted for scraping aufwuchs from rocks
• Medium-sized mbuna — Reaches about 4.5 inches (11 cm); needs at least 55 gallons
• Maternal mouthbrooder — Standard mbuna breeding; females carry eggs for 3 weeks

Species Overview

Common Name	Scrapermouth Mbuna, Trewavas’ Mbuna
Scientific Name	Labeotropheus trewavasae
Care Level	Intermediate
Temperament	Aggressive
Max Size	4–4.5 inches (10–11 cm)
Min Tank Size	55 gallons (208 liters)
Diet	Herbivore
Lifespan	8–10 years
Water Temp	76–82°F (24–28°C)
pH	7.8–8.6
Origin	Lake Malawi, Africa

Classification

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Cichliformes
Family	Cichlidae
Genus	Labeotropheus
Species	L. trewavasae

Origin & Natural Habitat

The Scrapermouth Mbuna is endemic to Lake Malawi in East Africa, where it has a wide distribution along the rocky coastlines of the lake. Unlike some mbuna species that are restricted to tiny geographic areas, L. trewavasae is found throughout the lake, which has led to the development of numerous geographic color variants. This wide distribution is also why the species isn’t considered threatened.

In the wild, Scrapermouth Mbuna inhabit rocky areas where they can exploit their specialized feeding anatomy. Their unique downturned mouth and fleshy snout are perfectly designed for scraping aufwuchs — the biofilm of algae, diatoms, and tiny invertebrates — from rock surfaces. They can graze effectively at angles that most other mbuna can’t reach, giving them a competitive advantage in their ecological niche.

The species was named in honor of Ethelwynn Trewavas, a renowned ichthyologist at the British Museum of Natural History who made significant contributions to cichlid taxonomy.

Appearance & Identification

The most immediately recognizable feature of the Scrapermouth Mbuna is its mouth — wide, flat, and positioned underneath a prominent, enlarged fleshy nose (rostral protuberance). This gives the fish an unmistakable facial profile that’s unlike anything else in the mbuna world. The mouth is designed to press flat against rock surfaces for efficient scraping, and the fleshy nose acts as a kind of bumper or guide.

Color variation in this species is extraordinary. Depending on the collection location, you might see males that are solid blue, blue with dark barring, or even orange. Females are often OB (orange blotched) — a marbled pattern of orange, brown, and cream that’s highly variable between individuals. Some locations produce yellow or spotted forms. This diversity means no two tanks of Scrapermouth Mbuna look exactly the same.

Male vs. Female

Sexual dimorphism in Scrapermouth Mbuna is often quite pronounced, especially in the typical blue male / OB female form.

Feature	Male	Female
Color (typical)	Rich blue with dark barring; yellow-brown anal/caudal fins	OB (orange blotched) — marbled orange, cream, brown
Size	Up to 4.5 inches (11 cm)	Slightly smaller, around 3.5–4 inches
Egg Spots	Prominent on anal fin	Fewer or absent
Body Shape	More robust, larger head	Slightly slimmer, rounder belly when gravid
Behavior	Highly territorial, especially during breeding	Generally more peaceful

Note that color patterns vary significantly by location, so not all populations follow the blue male / OB female pattern. Always purchase from a seller who can identify the specific variant.

Average Size & Lifespan

Scrapermouth Mbuna are a medium-sized species, typically reaching 4–4.5 inches (10–11 cm) in aquarium conditions. Males are slightly larger than females. Their stocky, robust build makes them look larger than their actual length suggests.

With proper care, Scrapermouth Mbuna can live 8–10 years in captivity. Their hardiness and adaptability contribute to their longevity, provided they receive consistent water quality and appropriate nutrition.

Care Guide

Tank Size

A 55-gallon (208-liter) tank is the minimum for a small group. For a mixed mbuna community, 75 gallons (284 liters) or more is strongly recommended. Given the territorial nature of males, the more space you provide, the better — a 4-foot or longer tank provides the horizontal territory these fish need.

Water Parameters

Temperature	76–82°F (24–28°C)
pH	7.8–8.6
General Hardness (dGH)	10–20 dGH
Carbonate Hardness (dKH)	10–15 dKH
Ammonia	0 ppm
Nitrite	0 ppm
Nitrate	<20 ppm

Standard Lake Malawi parameters. Buffer with aragonite substrate or crushed coral if needed. Consistency is key — avoid sudden swings in any parameter.

Filtration & Water Flow

Heavy filtration is essential. A quality canister filter rated for at least 1.5 times your tank volume, supplemented with a powerhead for circulation, provides the clean, well-oxygenated water these fish need. Weekly water changes of 25–40% are non-negotiable — more frequently if heavily stocked.

Lighting

Moderate lighting works well and encourages algae growth on rocks for natural grazing — something Scrapermouth Mbuna are perfectly adapted to take advantage of. An 8–10 hour photoperiod is ideal.

Plants & Decorations

Lots of rockwork with complex formations creating caves, passages, and territories. Scrapermouth Mbuna are not plant-compatible — they’re efficient herbivores that will make quick work of most aquarium plants. Skip the greenery and focus on creating an impressive rock aquascape with limestone, lava rock, or ocean rock.

Build multiple line-of-sight breaks to reduce aggression. Each male needs a definable territory with a cave, and subordinate fish need escape routes.

Substrate

Fine sand is recommended — aragonite sand for pH buffering, or a mix of pool filter sand and crushed coral. Scrapermouth Mbuna will rearrange the substrate in their territories, so sand accommodates this natural behavior better than gravel.

Tank Mates

Best Tank Mates

Scrapermouth Mbuna need tank mates that can hold their own. Choose robust species with different color patterns. Good options include:

• Yellow Lab (Labidochromis caeruleus) — Different color, usually manages well
• Red Zebra (Metriaclima estherae) — Tough enough to coexist
• Cobalt Blue Zebra (Metriaclima callainos) — Comparable temperament
• Demasoni (Pseudotropheus demasoni) — Both territorial but different enough in appearance
• Synodontis catfish — Hardy bottom dwellers that stay out of territorial disputes

Tank Mates to Avoid

• Peacock cichlids (Aulonocara spp.) — Too docile for a tank with aggressive mbuna
• Labeotropheus fuelleborni — Same genus; hybridization risk and doubled aggression
• Rusty Cichlids (Iodotropheus sprengerae) — Too peaceful; will be overwhelmed
• Any small or slow-moving species — Will be harassed relentlessly
• Haplochromis species — Most are too peaceful for a Scrapermouth tank

Food & Diet

The Scrapermouth Mbuna is a dedicated herbivore — arguably the most specialized plant eater among commonly kept mbuna. Their entire mouth structure is built for scraping algae from rock surfaces, and their diet in captivity should reflect this.

High-quality spirulina-based flakes or pellets should be the staple food. Supplement with blanched vegetables like spinach, zucchini, lettuce, and shelled peas. Algae wafers and nori sheets are excellent additions. If you encourage algae growth on your rocks with extended lighting, Scrapermouth Mbuna will graze on it naturally throughout the day.

Avoid high-protein foods entirely — no bloodworms, no beef heart, and minimal brine shrimp. Their herbivorous digestive system is highly susceptible to problems from protein-heavy diets. Feed 2–3 small meals per day.

Breeding & Reproduction

Scrapermouth Mbuna are maternal mouthbrooders, following the standard mbuna breeding pattern.

Spawning Behavior

Males become particularly aggressive and colorful during breeding season. The dominant male establishes and vigorously defends his territory, displaying intensely to passing females. The spawning follows the familiar egg-dummy routine — the female deposits eggs, picks them up in her mouth, and is attracted to the male’s anal fin egg spots, where she inadvertently picks up milt for fertilization.

Keep a ratio of 1 male to at least 3 females to distribute the male’s considerable aggression during breeding.

Mouthbrooding & Fry Care

The female carries the developing eggs for approximately 3 weeks. During this time, she won’t eat and will be noticeably reclusive. Clutch sizes vary depending on the female’s size and experience, but 15–30 fry is typical.

Once released, fry can take crushed spirulina flake, baby brine shrimp, and finely ground fry food. For the best survival rates, isolate the holding female in a separate breeding tank before release. The fry grow steadily with proper nutrition and clean water.

Common Health Issues

Malawi Bloat

As a strict herbivore, the Scrapermouth Mbuna is extremely susceptible to Malawi Bloat if fed an improper diet. Symptoms include abdominal swelling, white feces, loss of appetite, and rapid breathing. Fatal within 24–72 hours if untreated. Keep the diet plant-based and the water clean. Treat early with Metronidazole if caught in time.

Ich (White Spot Disease)

Stress from transport, poor water quality, or aggression can trigger ich. White spots on the body and fins are the telltale sign. Raise temperature to 82°F (28°C) and treat with ich medication. Scrapermouth Mbuna are hardy and respond well to treatment.

Aggression-Related Injuries

Territorial disputes can result in torn fins, missing scales, and scrapes. Minor injuries heal on their own with excellent water quality. More serious wounds may need antibiotic treatment. Providing ample rockwork and maintaining proper stocking ratios minimizes injury risk.

Common Mistakes to Avoid

• Feeding protein-heavy foods — These are strict herbivores. No bloodworms, no beef heart, minimal brine shrimp
• Mixing with L. fuelleborni — Same genus species will hybridize and aggression doubles
• Underestimating male aggression — Males are highly territorial; provide ample space and rockwork
• Keeping with peaceful species — Rusties and Peacocks will be overwhelmed
• Not enough hiding spots — Territorial disputes escalate quickly without adequate cover
• Attempting a planted tank — These fish will destroy plants efficiently; focus on rockwork instead

Where to Buy

Scrapermouth Mbuna are moderately available in the hobby. They’re less common than Red Zebras or Yellow Labs but can be found through specialized African cichlid retailers. Expect to pay $6–$15 per fish depending on the color variant and size. For quality stock:

• Flip Aquatics — Quality African cichlids including various Labeotropheus variants
• Dan’s Fish — Trusted source for mbuna species with reliable shipping

When purchasing, try to buy a group of at least 4–6 from the same variant/location to avoid hybridization and ensure visual consistency. Aim for a female-heavy ratio.

FAQ

What’s the difference between L. trewavasae and L. fuelleborni?

Both species share the distinctive Labeotropheus snout and mouth structure, but L. trewavasae is slightly smaller and more slender, while L. fuelleborni is stockier and more robust. Color patterns differ between the two species and their many geographic variants. They should never be kept together due to hybridization risk.

Why does my Scrapermouth have such a big nose?

That prominent, fleshy nose (called a rostral protuberance) is a specialized adaptation for feeding. It acts as a bumper or guide, allowing the fish to press its wide, flat mouth directly against rock surfaces for efficient algae scraping. It’s one of the most specialized feeding adaptations among mbuna.

Are Scrapermouth Mbuna good for beginners?

They’re better suited for intermediate keepers. While they’re hardy and not particularly difficult to care for, their aggressive temperament — especially males during breeding — requires experience managing mbuna aggression through proper stocking and tank design. Start with milder species like Yellow Labs or Rusty Cichlids first.

What color variants are available?

Quite a few. Common variants include “Thumbi West” (blue males, OB females), “Marmalade Cat” (orange/marbled), “Chilumba” (blue/red), and “Mpanga” (blue males, mottled females). The OB (orange blotched) female pattern is particularly popular and visually striking. Each geographic variant has its own distinct look.

Can I keep Scrapermouth Mbuna with plants?

Not recommended. Their specialized scraping mouth is incredibly efficient at removing plant material, and they will quickly demolish most aquarium plants. Stick to an all-rock aquascape for this species.

How long do Scrapermouth Mbuna live?

With proper care, they can live 8–10 years. Consistent water quality, a strictly plant-based diet, and proper tank management are the keys to reaching the upper end of that range.

Closing Thoughts

The Scrapermouth Mbuna is one of the most unique and visually interesting species in the Lake Malawi hobby. That distinctive face alone sets it apart from everything else in your tank, and the incredible variety of color forms means you can find a variant that appeals to almost any aesthetic preference. Add in their specialized feeding behavior and fascinating territorial displays, and you’ve got a fish that never gets boring to watch.

They’re not the easiest mbuna to manage — the males require respect, the diet needs to be strictly plant-based, and tank mate selection matters — but for intermediate to experienced keepers, Labeotropheus trewavasae is a genuinely rewarding species that offers something no other mbuna can.

This article is part of our Lake Malawi Cichlid Species Directory: Complete A-Z Care Guide List. Visit the hub page to explore care guides for all 28 Lake Malawi cichlid species we cover.

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References

• Seriously Fish. (n.d.). Labeotropheus trewavasae. https://www.seriouslyfish.com/species/labeotropheus-trewavasae/
• FishBase. (n.d.). Labeotropheus trewavasae, Scrapermouth Mbuna. https://www.fishbase.se/summary/Labeotropheus-trewavasae.html
• Practical Fishkeeping. (n.d.). Labeotropheus trewavasae species profile. https://www.practicalfishkeeping.co.uk
• The Aquarium Wiki. (n.d.). Labeotropheus trewavasae. https://www.theaquariumwiki.com/wiki/Labeotropheus_trewavasae