Blacktip Reef Shark

Geographic Origin and Biotope: Widespread throughout the tropical Indo-Pacific. Inhabits shallow coral reefs, flat sandy lagoons, and mangrove swamps. It is a coastal apex predator that often ventures into waters so shallow its dorsal fin is exposed, hunting crustaceans and small fish among mangrove roots.

Taxonomy and Morphology: Requiem shark of the Carcharhinidae family (Blacktip reef shark). Possesses a robust torpedo body, short and rounded snout. The unmistakable feature is the conspicuous black tips edged in white on all fins, particularly the first dorsal and caudal. In captivity, it rarely exceeds 160 cm (5.2 feet), but in the wild approaches 2 meters.

Social Behavior: Active and darting. Often forms small wandering hierarchical groups, especially during feeding or in nurseries. Extremely nervous and shy towards humans; tends to swim away quickly unless conditioned by food.

Coloration and Sexual Dimorphism: Brownish-gray or yellowish-brown back to blend with sandy bottoms viewed from above; pure white belly. The tips of each fin are marked with intense, ink-like black. Males are recognized by the presence of claspers under the pelvic fins, visible from a young age.

Aquarium Setup: Species NOT suitable for home aquariums. Requires public ocean tanks or cylindrical/oval tanks of tens of thousands of liters to prevent fatal collisions. The bottom must be fine sand, devoid of sharp rocky decorations that could flay its skin. A very strong circular water flow is imperative for respiration (ram ventilation).

Diet and Feeding: Active predator. The diet consists of cephalopods (squid, octopus), crustaceans, and bony fish (mullet, grouper). In large aquariums, it must be fed via long tongs with chunks of lean fish (hake, cod, salmon) supplemented with specific shark vitamins (especially iodine and vitamin C) to prevent thyroid goiter.

Water Quality: Extremely sensitive to water quality. Oceanic temperature: 24-28 °C (75-82 °F). Standard marine salinity (SG 1.023-1.026). Extremely high need for dissolved oxygen and colossal filtration with gigantic protein skimmers to remove massive nitrogenous waste (urea) without affecting the alkaline pH (8.1-8.4).

Compatibility and Tankmates: In immense tanks, coexists with large Trevallies, Batfish (Platax), giant groupers, and other species of sharks or benthic rays. Will inevitably ingest any fish smaller than its mouth or in distress. Absolutely incompatible with slow fish or those with venomous spines (Lionfish) that could kill it during a predation attempt.

Aquarium Reproduction: Viviparous placental (a rarity among fish). After a gestation of 10-16 months (depending on water temperature), the female gives birth to 2 to 4 live, fully independent pups in very shallow waters. Reproduction has been successfully recorded in several large public aquariums.

Risks and Diseases: Unsuited for confined spaces: bumps into glass causing damage to the rostrum resulting in fatal bacterial infections. Vulnerable to "goiter" (iodine deficiency) and monogenean parasites on the gills. Excess nitrates lead to lethargy, food refusal, and death in a few weeks.