First of all, the fish known as sharks and kept in the home aquarium bear no relation to Jaws, or indeed to any of the other varieties of shark found at sea. They get their common names from their passing resemblance to their bigger namesakes in terms of appearance and movement. All the varieties (and their albino forms) are popular choices for community tanks, though they need to be considered with care, as they are not the friendliest of tankmates either with each other (only one adult of any of the types should be kept at a time due to potential territorial squabbles ) or with many other popular fish – notably ones that are smaller than they are, and will be seen increasingly, as the shark grows, as snacks rather than friends. They also need plenty of space, as, even though they are only tiny in the shop as babies, red tailed black sharks and ruby sharks soon grow to 15cm (6″) while silver sharks can reach a whopping 35cm (14″).
Red Tail Black shark