Petrochromis trewavasae 5-6 cm | Trewavas' Petrochromis

Overview

Petrochromis trewavasae, commonly known as Trewavas' Petrochromis, is a distinctive Lake Tanganyika cichlid prized by experienced aquarists for its rugged character, fascinating behaviour and specialised grazing habits. Offered here at 5-6 cm, these juveniles are a superb choice if you want to raise a fish with real presence and watch it develop into a powerful adult.

This species is not a community fish in the usual sense. It is best suited to a carefully planned Tanganyika setup with hard, alkaline water, plenty of rockwork and a diet focused on vegetable matter and algae-based foods. When kept correctly, Petrochromis trewavasae is active, engaging and long-lived, making it a rewarding species for dedicated cichlid keepers.

At Tropical Fish Co, all livestock is packed with care and sent with fast UK delivery, plus our live arrival guarantee for peace of mind. Please note that this is a specialist fish and should only be purchased by aquarists prepared to meet its water and territorial needs.

Care at a Glance

Origin & Natural Habitat

Petrochromis trewavasae is endemic to Lake Tanganyika, one of the world’s oldest and most biologically diverse lakes. In the wild, Petrochromis species inhabit rocky shorelines where strong wave action, abundant sunlight and mineral-rich water support heavy algal growth. These fish spend much of their time scraping and browsing aufwuchs from rocks, using their specialised mouths to feed on the thin layer of algae and associated microorganisms.

That natural lifestyle explains much of their aquarium behaviour. They are active grazers, constantly exploring surfaces and defending feeding territories. Their environment is highly stable, warm, alkaline and hard, so they do best in water that reflects those conditions as closely as possible. Soft, acidic water is unsuitable and can lead to stress and poor health.

Tank Setup & Water Parameters

Because this species becomes territorial and robust as it matures, a spacious aquarium is essential. We recommend a minimum of 400 litres for a single specimen or a carefully managed group, with larger tanks strongly preferred for long-term success. The aquarium should be built around substantial rockwork arranged to create caves, ledges and broken lines of sight. This helps reduce aggression and gives each fish defined territories.

Use a sandy substrate or fine coral sand if desired, and avoid sharp decorations that could damage the fish during territorial displays. Open swimming space is important, but so is structure. A good Tanganyika tank for Petrochromis trewavasae should look like a rocky shoreline rather than a planted community aquarium.

Water movement and oxygenation should be strong, with efficient filtration and regular maintenance. Lake Tanganyika fish appreciate clean, well-oxygenated water with minimal waste build-up. Weekly water changes are recommended, and stable water chemistry is more important than chasing exact numbers.

Ideal parameters are:

• Temperature: 24-27°C
• pH: 7.5-8.5
• Hardness: 12-30 dGH

Because this species is a herbivorous grazer, avoid overfeeding protein-rich foods. A diet too heavy in meaty items can cause digestive issues and poor condition. Good filtration, rockwork and a sensible feeding regime are the keys to keeping this cichlid thriving.

Feeding Guide

In nature, Petrochromis trewavasae feeds mainly on algae and the biofilm growing on rocks. In the aquarium, the diet should be based on high-quality spirulina flakes, algae wafers, vegetable-based pellets, blanched greens such as spinach or courgette, and other plant-rich foods. Occasional small amounts of suitable frozen foods may be accepted, but these should not form the bulk of the diet.

Feed small portions several times a day if possible, especially while the fish is growing. This species is an active grazer and benefits from regular access to suitable food. Remove any uneaten food promptly to maintain water quality. A varied, vegetable-led diet will help support colour, growth and long-term health.

As with many Tanganyika cichlids, it is best to avoid fatty foods and excessive animal protein. Consistency is more important than quantity.

Tank Mates / Compatibility

Petrochromis trewavasae is best kept with other robust Lake Tanganyika species that can tolerate similar water conditions and hold their own in a territorial environment. Suitable companions may include other Tanganyikan cichlids of comparable size and temperament, provided the aquarium is large enough and the layout is carefully planned.

Good tank mates can include some Julidochromis, Neolamprologus species, and other sturdy Tanganyika cichlids where compatibility and tank size allow. However, mixing with similar-shaped or similarly territorial Petrochromis can be risky unless the aquarium is very large and the aquarist has experience managing aggression.

Avoid slow, timid fish, small community species, and any fish that require soft or acidic water. Also avoid delicate invertebrates, as they are not suitable companions. This is a specialist cichlid for a specialist setup, not a general community aquarium.

When introducing new fish, do so carefully and monitor behaviour closely. Providing multiple rock piles and visual barriers can help reduce conflict. In many cases, it is best to plan the stocking around one dominant Petrochromis rather than forcing it into a crowded mix.

Why Buy from Tropical Fish Co

At Tropical Fish Co, we understand that specialist fish need specialist care from the moment they are packed to the moment they arrive. Our livestock is selected with quality and welfare in mind, and every order is handled carefully to help ensure your fish arrive in excellent condition. We offer fast UK delivery and a live arrival guarantee, so you can order with confidence.

We also aim to provide clear, honest care information so you can prepare the right environment before your fish arrives. If you are building a Tanganyika display and want a truly distinctive cichlid with character, Petrochromis trewavasae is an outstanding choice for the experienced aquarist.

Order your 5-6 cm juvenile today and enjoy the rewarding experience of raising one of Lake Tanganyika’s most impressive rock-dwelling cichlids.