Amongst the "real shark" looking sharks offered in the aquarium trade (other than those Nurse Sharks, Leopards, Epaulettes, Bamboo, Catsharks... that spend so much time "just sitting on the bottom", is the Requiem Shark (family Carcharhinidae) member Carcharhinus melanopterus (most often sold as the Blacktip Shark, though this is another species... C. limbatus.)

    Unfortunately, this shark is entirely unsuitable for home aquarium use, requiring a pool-sized enclosure (thousands of gallons) to do well. Though folks can/do keep small specimens of the Blacktip Reef Shark, aka the Reef Blacktip Shark in much smaller systems for a time, invariably these are short term successes, with the specimens almost always dying "mysteriously", crashing into the tanks side, or jumping out.

    As with all the other forty nine species of Requiem Sharks, you're encouraged to go visit them in the ocean or Public Aquariums.

Range:

    Widely distributed in the tropical Indo-Pacific from the Red Sea, along the eastern African Coast over to Hawai'i down to the Tuamotu Islands. Oh, and in the Mediterranean by way of the Suez Canal.

Size:

    Mostly very small juveniles are offered in the trade, in the fifteen to eighteen inch total length range. This species grows to about six feet total length... not to be confused with that "other" Blacktip Shark. Carcharhinus limbatus tops out at more than ten feet.

Selection:

    As sharks go, particularly the "active shark-looking types", the Reef Blacktip ships quite well... For such active animals, as you might guess, they command a high price due to the large shipping containers, water weight involved in their transport. 

    If you're involved in the outright purchase of these animals look for full, regular locomotion, clear smooth skin (no white patches or bloody marks. Look especially at the base of the fins for the latter.

Environmental: Conditions

Habitat

    As mentioned over and over, a very large living space is needed to keep constantly moving shark species. In the wild a typical foraging area for this species is one square mile. Shape of the system is important, and something with more rounded corners (versus square) is a definite plus. With and w/o provocation these sharks will at times take off at "lightning speed" crashing into holding system walls. Best if these are glancing blows. 

    Rockwork on the bottom and/or back is a plus, giving other likely tankmates places to hide/be. Do leave the upper area and a good part of the bottom open free and clear however as carcharhinids need room to move... for foraging, respiration and being themselves. 

    A heavy, tight-fitting cover for their enclosures is needed as these sharks can launch themselves free of the water... and how. They will jump out given the opportunity. 

Behavior

Territoriality:

    Reef Blacktip Sharks of different size can/will bite, eat one another if very hungry, but practically speaking, they can be placed together with relative impunity. 

Predator Prey Relations:

    On the reef, Carcharhinus melanopterus principally feeds on other fishes of many types (including triggerfishes, surgeonfishes, wrasses...), then in preponderance of diet, cephalopods (squid, octopus), crustaceans, and a large percentage of sea snakes in some parts in the wild. It is likely safe to state that any edible tankmate/portion of a captive system is game for their consumption.

Collection

    These sharks are collected in a few "standard" ways and a few that are quite novel. There are accounts of a "shark hunting dog" (see bibliography below), the usual barbless baited hook... and an occasional "lucky catch" by tropical collectors using barrier nets et al. One such circumstance was related to me by a friend/collector, Eric Rood that occurred during his time in Hawai'i. A fence, barrier net had been placed and a group of tangs driven into it for hand-netting when a small Blacktip Reef Shark "hit the net" full speed coming from behind. Collecting divers are always on guard for removing ("pushing" them over the top, float line) such marauding non-prey as triggerfishes, parrotfishes... lest these non-invitees chew  a hole through their barrier nets, making a way for the intended catch to escape, and ending the days fishing. Eric "dropped everything" and once he realized what it was, carefully grabbed the shark (by hand, as it is easy to damage these fishes with netting) and placed it in his holding container). A good catch, as these sharks fetch high collectors pay.

    In aquariums care must be taken not to "spook" captive sharks. What is called for are slow, deliberate motions, multiple nets/friends, damp towels to hold onto, and if necessary, lift the specimen/s from the water. Remember, carcharhinids are faster than you'll ever be. The tale about striking them on the nose (same family includes the "Great White", "Tiger"...) to avoid predation are myths. 

Foods/Feeding/Nutrition

    Regularly scheduled (same time, place, types of foods) of small fishes, squid (though messy, do clean, offer just the mantles) in an upper part of the tank (not by hand, use tongs) are advised. Daily amounts are best in my opinion, experience, for such small sharks. Some keepers, and all public aquariums that I'm aware of, insert vitamin supplements into these foods ahead of offering.

Disease Prevention/Treatment

    Healthy Blacktip Reef Sharks tend to stay that way, or be dead with little notice. The species is susceptible to cryptocaryon if very stressed, exposed to a going hyperinfection, and a fluke (monogenetic trematode), Dermophthirius melanopteri, the causative organism for the white-patch syndrome mentioned under "selection". The latter is easily treated with organo-phosphates like Trichlor, Neguvon, masoten, dylox, DTHP... (all the same chemical).

Conclusion:

    This common small carcharhinid is often seen in the wild, despite its popular use as a food fish. When on a dive adventure vacation, ask the local folks about the "little tan shark with black tipped fins". If it can be located in the area, they will know where to find it. Very small young "hang out" feeding and avoiding predators in the shallows in the morning and evening.

    Yes, I've seen this species kept in captivity, in public and private settings. It can be done, but the vast majority of trials result in short lived, traumatized owners and dead sharks. Try a more suitable species if so inclined to shark keeping. 

Bibliography/Further Reading:

Sharks and Rays in Aquariums Gaining an understanding of how to keep these fishes in captive saltwater systems    New Print and eBook on Amazon: Available here  by Robert (Bob) Fenner