Apogonichthyoides melas (M) Black Cardinalfish

Overview

Apogonichthyoides melas, commonly known as the Black Cardinalfish, is a distinctive marine species prized for its deep dark colouration, peaceful temperament and nocturnal habits. This medium-sized cardinalfish is a great choice for aquarists looking to add character to a reef-safe community tank without introducing aggression. It is best suited to calm marine setups with plenty of shelter, subdued lighting and stable water conditions.

Cardinalfish are known for their relatively easy-going nature compared with many other saltwater species, and A. melas is no exception. It spends much of the day resting in shaded areas, rockwork caves or overhangs, becoming more active at dusk and during feeding times. In the right environment, it can settle well and display confident behaviour, especially when kept in a peaceful group or with suitable tank mates.

At Tropical Fish Co, we supply healthy marine livestock with care and attention, backed by a live arrival guarantee and fast UK delivery. If you are building a tranquil marine display and want a fish with real presence, the Black Cardinalfish is an excellent option.

Care at a Glance

Origin & Natural Habitat

Apogonichthyoides melas is a marine cardinalfish found in the Indo-West Pacific region, where it inhabits coastal reefs, lagoons and sheltered inshore waters. In nature, it prefers areas with structure and cover such as coral heads, rocky crevices and ledges. These habitats provide protection from predators and allow the fish to remain hidden during daylight hours.

This species is adapted to a life among shaded reef structures and is often most active at night. Its natural behaviour reflects a fish that values security and low-stress surroundings. Recreating this environment in the aquarium is the key to success: stable salinity, plenty of hiding places and gentle tank mates will help it thrive.

Tank Setup & Water Parameters

A mature marine aquarium with live rock, caves and overhangs is ideal for the Black Cardinalfish. Because it is a shy, shelter-seeking species, aquascaping should prioritise secure retreats rather than open swimming space alone. A tank of at least 200 litres is recommended, especially if keeping more than one specimen or housing it with other peaceful marine fish.

Provide subdued lighting where possible, or ensure there are shaded zones within the aquascape. Strong, direct lighting is not usually a problem if there is adequate cover, but the fish will be more comfortable when it can retreat from bright areas. A tight-fitting lid is advisable, as cardinalfish can jump when startled.

Maintain excellent water quality with regular testing and consistent husbandry. As with all marine fish, sudden swings in salinity, temperature or pH should be avoided. Good filtration, moderate flow and routine water changes will help keep the fish healthy and reduce stress.

• Temperature: 24–28°C
• pH: 8.0–8.4
• Salinity: Stable marine salinity, around 1.023–1.026 SG
• Tank size: 200 litres minimum
• Decor: Live rock, caves, shaded ledges and secure hiding places
• Flow: Moderate, not overly turbulent

Acclimation should be slow and careful, as marine fish can be sensitive to changes in salinity and temperature. Once settled, this species is generally hardy provided the aquarium is stable and peaceful.

Feeding Guide

The Black Cardinalfish is a carnivorous species that should be offered a varied diet of quality marine meaty foods. In the wild it feeds on small crustaceans, zooplankton and other tiny animal matter. In captivity, it will do best on a mix of frozen and prepared marine foods such as mysis shrimp, enriched brine shrimp, chopped krill, finely diced seafood and suitable carnivore pellets or granules.

Because this species is often more active at dusk and night, feeding in the evening can improve response, especially when newly introduced. Small, regular meals are preferable to large feedings. As with many cardinalfish, some individuals may initially be shy feeders, so offering food near their shelter can help encourage them.

A varied diet supports colour, condition and long-term health. Avoid relying solely on low-nutrition flake foods. For best results, rotate foods and ensure any frozen items are marine-quality and appropriately enriched.

Tank Mates / Compatibility

Apogonichthyoides melas is best kept with calm, non-aggressive marine species that will not outcompete it for food or harass it. It can be a good addition to reef-safe community systems where tank mates are similarly peaceful and not overly boisterous.

Suitable companions may include other gentle reef fish, such as small gobies, blennies, clownfish, firefish, chromis and some peaceful wrasses, provided the overall tank dynamics remain calm. It is also generally reef-safe with corals and invertebrates, although care should always be taken with individual behaviour and tank size.

Avoid aggressive species, highly territorial fish and fast, dominant feeders that may stress the cardinalfish or prevent it from eating. Large predatory fish should also be avoided, as the Black Cardinalfish is small enough to be viewed as prey by many larger marine species.

Introduce tank mates carefully and provide enough hiding spaces for all fish. If kept in a group, ensure the aquarium is spacious and well-structured to reduce competition and allow each fish to establish a secure retreat.

Why Buy from Tropical Fish Co

At Tropical Fish Co, we understand that buying marine livestock online requires confidence, care and reliable service. That is why we focus on healthy stock, careful packing and prompt dispatch, helping your fish arrive in the best possible condition. Our fast UK delivery service is designed to minimise transit time and reduce stress on your new arrival.

We also offer a live arrival guarantee, giving you added peace of mind when ordering online. Every fish is selected with quality in mind, and we aim to provide clear, accurate information so you can choose the right species for your aquarium.

Whether you are building a peaceful reef community or adding a unique nocturnal character fish to a marine display, Apogonichthyoides melas is a rewarding choice. With the right setup, it can become a long-lived and fascinating resident of your aquarium.