Saltwater

The Banggai cardinalfish (Pterapogon kauderni) is one of the most recognizable and best-loved marine aquarium fish. Its silver body, bold black bars, long trailing fins and white-spotted tail make it unforgettable, and it is a calm, slow-moving fish that suits peaceful reef tanks. It is also one of the few marine fish regularly bred in

The kole tang (Ctenochaetus strigosus), also called the yellow-eyed kole tang or goldring bristletooth, is a favorite of reef keepers. It combines a handsome look with an excellent work ethic: it grazes film algae and detritus all day, and is among the few tangs that are generally safe with corals. It is not a beginner

The bluestreak cleaner wrasse (Labroides dimidiatus) is one of the most charming fish on the reef, and one of the hardest to keep alive in an aquarium. In the wild it eats parasites and mucus picked off dozens of client fish a day. Most captive specimens slowly starve, and the hobby’s honest advice is that

The green spotted puffer (Dichotomyctere nigroviridis, formerly Tetraodon nigroviridis) is a bold, intelligent and endlessly entertaining fish. It is also one of the most commonly mis-sold fish in the hobby. Stores often label it “freshwater”, but it only does well short term in fresh water and needs brackish and eventually near-marine conditions as an adult.

The blood red fire shrimp (Lysmata debelius) is one of the most striking invertebrates in the saltwater hobby: deep crimson with bright white spots and long white antennae. They are shy, reef-safe in most cases and fascinating to watch, but they are less forgiving than they look. This fire shrimp care guide covers everything from

Emerald crabs (Mithraculus sculptus) are small, green, hairy-bodied reef crabs best known for eating nuisance algae, including bubble algae and hair algae, but they are not guaranteed reef safe. Most are peaceful scavengers that do a great job cleaning rock, yet some individuals, especially larger ones, will nip at corals, snails or even small fish

The powder blue tang is one of the most striking fish in the saltwater hobby. It has a bright blue body, a yellow dorsal fin, and a black face with a white chin. It is also one of the most challenging tangs to keep alive. Many are lost to ich, stress and starvation within the

The bicolor blenny (Ecsenius bicolor) is one of the best-known personalities in the saltwater hobby. It perches on rocks, pokes its head out of holes, and nibbles algae all day. It is hardy and reef safe in most tanks, but it has quirks that matter. Here is what bicolor blenny care really involves. Overview and

Seahorses are some of the most fascinating animals in the hobby, and also some of the most demanding. They are slow, shy, poor swimmers that eat only live or frozen foods and are easily stressed or outcompeted by faster tank mates. Done right, a seahorse tank is a calm and rewarding display. Done carelessly, it

Few marine invertebrates are as striking as the harlequin shrimp (Hymenocera picta). With pastel white, pink and blue-spotted bodies and paddle-shaped claws, it looks like something from a fantasy reef. It is also one of the hardest shrimp to keep, because harlequin shrimp eat living starfish and little else. If you can’t supply a steady