Thomas Pelmatochromis, Dw (Pelmatochromis thomasi) — 2-3cm

Overview

The Pelmatochromis thomasi, commonly known as Thomas's Pelmatochromis or Thomas Dwarf Cichlid, is a charming West African species that brings authentic Congo River basin character to modest aquariums. Reaching just 4.5 cm and requiring a minimum 80-litre aquarium, this compact cichlid offers fascinating breeding behavior and manageable care requirements for aquarists seeking alternatives to more aggressive cichlids. Endemic to the lower Congo River and adjacent coastal drainages, this semi-aggressive species rewards keepers who provide soft, acidic water and well-structured aquariums with caves for spawning. Available to buy online UK from Tropical Fish Co, this freshwater fish uk represents an excellent introduction to West African dwarf cichlids for aquarists transitioning from community setups to specialized species.

Appearance

Pelmatochromis thomasi displays the compact, robust proportions characteristic of dwarf cichlids, with a well-defined head and alert expression suggesting intelligence and awareness. Base coloration ranges from olive-brown to grey-green, with males typically developing more vibrant colors during breeding periods including blue-green iridescence on the face and gill covers, and warm orange or reddish tones on the belly and lower fins. Females show more subdued coloration but may display a distinctive "cherry spot" on the dorsal fin when breeding. The streamlined body and proportionate finnage reflect adaptations for maneuvering through complex root systems and rocky structures in West African streams. Sexual dimorphism becomes more pronounced during maturity, with breeding pairs displaying their most intense coloration.

Natural Habitat

This species inhabits slow-moving rivers, forest streams, and coastal drainages throughout the lower Congo River basin in West Africa. These environments feature warm, soft, slightly acidic water (pH 6.0-7.2) stained tea-brown from dissolved tannins and humic acids leaching from surrounding vegetation. Pelmatochromis thomasi shelters among submerged roots, leaf litter, and rocky structures, establishing territories around preferred caves and feeding on small invertebrates and organic matter. Seasonal water level fluctuations create dynamic habitats, though this species typically occupies areas with relatively stable conditions year-round. The complex structure of natural habitats—with countless hiding places and territorial boundaries—shapes the species' behavior and requirements in aquarium settings.

Aquarium Setup

An 80-litre aquarium provides adequate space for a pair of Pelmatochromis thomasi, with larger volumes supporting additional compatible tankmates if desired. Create a West African biotope using sand or fine gravel substrate, generous driftwood providing caves and visual barriers, and scattered smooth rocks. Hardy plants such as Anubias, Java fern, and Cryptocoryne species tolerate the soft, acidic water these cichlids require while providing additional structure. Provide multiple caves—terracotta pots, coconut shells, or driftwood structures—as spawning sites, with subdued lighting from floating plants or surface cover reducing stress. Install efficient filtration providing 5-6x tank volume turnover per hour, avoiding excessive current that stresses fish adapted to slow-moving waters. Leaf litter from oak or Indian almond leaves replicates natural habitats while providing mild antibacterial benefits.

Water Parameters

Maintain soft, slightly acidic water reflecting the species' West African origins: temperatures between 22-26°C and pH values from 6.0-7.2 in soft water (2-10 dGH). If your tap water is naturally hard, consider using RO water remineralized to appropriate parameters, or mix RO water with tap water to achieve softer conditions. Stability matters enormously—avoid rapid pH fluctuations that stress fish adapted to stable forest stream conditions. Conduct weekly 25-30% water changes to control organic waste accumulation and maintain water quality, with ammonia and nitrite always at 0 ppm and nitrates below 40 mg/L. The addition of peat filtration or botanicals provides tannins that replicate natural water chemistry while offering stress-reducing properties.

Feeding

As an omnivore, Pelmatochromis thomasi requires a varied diet replicating the small invertebrates and organic matter it consumes in West African streams. Feed quality cichlid pellets or micro-pellets as the staple, supplemented several times weekly with frozen and live foods including bloodworms, daphnia, brine shrimp, and other small invertebrates. Include occasional vegetable matter such as spirulina flakes or blanched vegetables to ensure complete nutrition and digestive health. Feed small portions 2-3 times daily, ensuring all food is consumed within a few minutes to maintain water quality. The small adult size necessitates appropriately sized foods—avoid pellets too large for comfortable consumption. Breeding pairs exhibit increased appetite as they prepare to spawn and during fry-rearing, requiring additional feeding without overfeeding that degrades water quality.

Behaviour

Pelmatochromis thomasi displays typical dwarf cichlid behavior with territorial tendencies that intensify during breeding. Pairs form strong bonds and establish territories around preferred caves, defending them against conspecifics and other bottom-dwelling fish. Aggression levels remain moderate outside breeding periods, allowing coexistence with appropriate tankmates in sufficiently structured aquariums. During spawning and fry-rearing, defensive behavior increases dramatically as parents protect eggs and fry against all perceived threats. The species demonstrates intelligence and personality, learning to recognize feeding schedules and individual keepers. Much of its time is spent patrolling territories, investigating caves, and picking at substrate for food particles—creating constant activity that makes pairs fascinating to observe in properly maintained aquariums.

Tank Mates

Compatible tankmates include small, peaceful West African species with similar water requirements such as small Congo tetras, African red-eye tetras, or peaceful barbs. Fast, non-fin-nipping midwater fish of similar size work well in spacious aquariums with plenty of cover. Other tankmates should only be considered in larger aquariums with substantial structure creating distinct territories. Completely incompatible are very small fry or shrimp that may be consumed, slow long-finned fish that will be harassed, highly aggressive cichlids that may injure or kill this small species, overly boisterous tankmates that cause constant stress, and other bottom-dwelling territorial cichlids in small tanks where territorial conflicts become unavoidable. During breeding, even supposedly compatible tankmates may require removal as parental aggression escalates dramatically.

Breeding

Pelmatochromis thomasi is a cave spawner that readily breeds when maintained in appropriate conditions. Bonded pairs select caves or sheltered sites where females deposit 80-150 adhesive eggs on cave ceilings or walls. The female typically guards eggs and newly hatched fry closely while the male defends the broader territory against intruders. Provide multiple caves, subdued lighting, and excellent water quality with stable parameters. Eggs hatch within 2-3 days depending on temperature, with fry becoming free-swimming approximately one week later. Feed fry infusoria initially, progressing to newly hatched brine shrimp and finely crushed flake foods within days. Both parents may shepherd fry around the territory, though the female assumes primary fry care. Parental care continues for several weeks until fry reach sufficient size to disperse independently.

Why Buy from Tropical Fish Co

Tropical Fish Co specializes in buy tropical fish uk, offering exceptional quality West African cichlids like Pelmatochromis thomasi with comprehensive care support. Our fish arrive carefully acclimatized and quarantined, backed by our industry-leading health guarantee. We provide expert guidance on creating authentic West African biotopes, maintaining soft acidic water chemistry, and successfully breeding dwarf cichlids. With decades of combined experience keeping specialized African species, we understand the unique requirements and rewards these charming fish offer. Order your Thomas Dwarf Cichlid from the UK's premier source for quality freshwater species and experience the fascinating behavior of West African dwarf cichlids in your home aquarium.