Moensis killifish
Fundulopanchax moensis
The Mo River killifish displays striking metallic blue scales and a distinctive elongated body, typically measuring around 3 inches in length.
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About the Moensis killifish
A small West-Central African killifish from rainforest streams in Cameroon's Cross River system. Males show bright blue with red spotting and colorful fins, and they court actively and place eggs in fine plants or peat. It is rarely seen in shops but has a following among killifish specialists.
Also known as
Quick Facts
Size
6.5 cm
Temperament
Semi-aggressive
Difficulty
Intermediate
Min Tank Size
30 gallons
Lifespan
3-5 years
Origin
West-Central Africa
Diet
Carnivore - live and frozen foods (e.g., Artemia, Cyclops); dry foods often refused
Water Parameters
22-24°C
6-7
4-8 dGH
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This species needs 22-24°C in a 30 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Give them at least 30 US gallons and pack in fine-leaved plants or peat fiber so they have places to lay eggs and to break up lines of sight.
- Keep water at 22-24 C, pH 6-7, and 4-8 dGH, and hold those values steady rather than bouncing them around.
- Feed small live and frozen foods (Artemia, Cyclops, similar); many refuse dry foods, so do not plan on flakes or pellets.
- They are semi-aggressive for their size, so a species tank or very carefully chosen tankmates is safer than a busy community.
- If you want fry, offer spawning mops, fine plants, or peat and collect eggs from the medium to rear in a separate container.
- Males court actively; give females dense cover so they can get out of sight when they need to.
- This fish is rarely in shops; try specialist breeders and confirm the name Fundulopanchax moensis to avoid mix-ups.
Compatibility
Good Tankmates
- Peaceful midwater schooling tetras that like soft, slightly acidic water at 23-24 C (e.g., black neon, lemon) - quick enough to avoid attention and not fin-nippy
- Corydoras catfish (cool-tolerant species like C. paleatus) - peaceful bottom dwellers that ignore the killifish's surface territory
- Otocinclus catfish - gentle algae grazers that stay on plants and glass; water parameters match and they avoid the upper zone
- Single small bristlenose pleco (Ancistrus) - hardy bottom grazer that keeps to itself and suits 22-24 C, pH 6-7, soft water
Avoid
- Fin-nippers and boisterous schooling fish (tiger barbs, serpae tetras, giant danios) - will shred fins or provoke fights
- Slow or long-finned fish (bettas, fancy guppies, gouramis, angelfish) - easy targets for chasing and nipping; many also prefer warmer or harder water
- Shrimp and tiny inverts (Neocaridina/Caridina, small snails) - likely to be hunted and eaten by this carnivore
- Other surface-dwelling killifish and territorial cichlids (Fundulopanchax/Aphyosemion spp., kribensis, jewel cichlids) - high aggression, competition at the surface, and risk of hybridization with other killis
Moensis killifish (Fundulopanchax moensis) is a small, striking freshwater species from West-Central Africa. Adults reach about 6.5 cm, live 3-5 years, and show semi-aggressive behavior in the aquarium. Males are the showpieces, with bright blue bodies, red spotting, and colorful fins. Care is intermediate, and the species is uncommon in shops but well regarded by killifish specialists.
This species is rarely offered in general fish stores. Most keepers encounter it through specialist breeders and clubs.
Origin and natural habitat
Fundulopanchax moensis comes from rainforest streams in Cameroon's Cross River system. Water there is soft and slightly acidic to neutral, and the fish are adapted to these stable, shaded stream environments.
Aquarium setup and water conditions
Give them space and cover. Although small, they appreciate a roomy tank for territory and display. Fine-leaved plants are useful, especially if you plan to breed them.
- Minimum tank size: 30 US gallons
- Temperature: 22-24 C
- pH: 6-7
- Hardness: 4-8 dGH
Use a tight-fitting lid. Like many killifish, F. moensis can and will jump.
Aim for clean, well-oxygenated water with gentle filtration. Planting and visual breaks help reduce sparring between fish.
Diet and feeding
This is a carnivore that does best on live and frozen foods. Offer small items such as Artemia and Cyclops, adjusting portion size to what they will eat quickly. Feed modest amounts once or twice daily and remove uneaten food to keep water quality high.
Dry foods are often refused. Plan to provide live and frozen fare as the staple.
Behaviour and tankmates
Moensis killifish are semi-aggressive. Males display and may spar, especially in tight quarters. A spacious, well-structured tank goes a long way toward keeping the peace.
- Best in a species-only setup if you want to see natural behavior and breeding displays.
- If choosing companions, select peaceful fish that share the same water requirements and are not fin-nippers.
- Avoid very small or slow, long-finned fish that could be harassed.
Breeding
Captive breeding is established for this species. Males court actively, and pairs place eggs among fine plants or in peat fiber. In aquaria, breeders often provide spawning mops or a container of rinsed peat to collect eggs.
Eggs are usually incubated separately from the adults. Once the fry hatch, start them on very small live foods; newly hatched Artemia is commonly used by killifish keepers. Keep water parameters close to those of the adults.
Common problems and how to avoid them
- Jumping: Always keep a tight cover with no gaps.
- Food refusal: Expect little interest in dry foods; stock reliable live and frozen options.
- Aggression in cramped tanks: Provide the full 30 gallons, dense planting, and sight breaks.
- Water chemistry drift: Stick to soft, slightly acidic to neutral water and stable temperatures within 22-24 C.
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