A large, aggressive species, such as a queen triggerfish, is sometimes best kept singlyA diverse community of marine fishes presents quite a visual feast, especially when housed in a reef system brimming with colorful corals. However, in some stocking situations, it’s preferable to avoid the “typical” marine community (if there is such a thing) in favor of a single-species or even a single-specimen tank. Ah, but if you limit your livestock to a single species or specimen, won’t that make for a real yawner of a tank? On the contrary, sometimes systems that put the focus exclusively or primarily on a particular species or individual are among the most fascinating to observe.Here are five circumstances that warrant going single-species or single-specimen: 1. The shy, specialized feeder Seahorses, which are slow, awkward swimmers, shy by nature, and very specialized, methodical feeders, come to mind here. In your average community aquarium, these fish would basically be doomed, as they’d be unable to compete with bolder, faster-moving tankmates for food and would be unable to tolerate the brisk water movement typical of such systems. Not to mention, a community tank of any appreciable size would make it extremely difficult to provide the steady supply and high concentration of suitable food items necessary to sustain seahorses. On the other hand, in a small dedicated system with very gentle current, no competition for food, and suitable “hitching posts” to cling to, a group of seahorses can make for a truly mesmerizing display
Threadfin Cardinalfish (Zoramia leptacantha)Walk by an LFS sales tank containing a few specimens of threadfin cardinalfish (Zoramia leptacantha), and you might not give them a second glance. Chromatically speaking, this species isn’t exactly a showstopper compared to some, especially when viewed in your average LFS environment. But don’t let this cardinal’s unassuming appearance fool you; it can make for an impressive display species when kept in groups. Physical traitsZ. leptacantha is a diminutive fish, reaching only about 2.5 inches in total length. It’s laterally compressed and has two dorsal fins, the first fairly elongated relative to the second. As mentioned, this species’ color is nothing to write home about (in case you’re one of those types who like to write home about the colors of fish). It’s semi-transparent to yellowish-silver overall with iridescent blue around the eyes as well as blue and yellow accents on the anterior portion of the body.
Notice the lateral line on this Anthias in my tankEverything about fish is amazing and fascinating. To me, the most fascinating thing about fish (beside their taste) is their lateral line system. The lateral line is the most important thing fish possess because without it, they would get around about as well as a supermodel in a bikini but no high heels. All fish have a lateral line, and you can usually see it. It is a line of scales that are slightly different from the rest of the fish’s scales, and they run from near their mouth, around the eye, to the tail. That line is made up of epithelial cells, which are basically modified skin cells. They are mucus-filled canals that have hair cells in them—kind of like what we have in our ears to help us determine which direction our spouse is yelling at us from. For our participation in this hobby, we don’t need to know exactly how all this works, but you can delve into it if you desire.Basically, the lateral line system allows the fish to know what is around it, what it is chasing, and how close it is to anything solid, including other fish, which is how millions of fish can swim in a school and never touch each other
Coral catfish (Plotosus lineatus)A school of juvenile coral catfish (Plotosus lineatus) rolling and wriggling en masse along the ocean floor is among the more endearing sights one can behold in the marine realm. Not surprisingly, after seeing this phenomenon in nature or on video, many hobbyists are inspired to recreate it in their home aquaria. What’s more, individual juveniles of the species—the only catfish found on tropical coral reefs—are irresistibly cute, so even those hobbyists who have never observed their schooling behavior may be charmed by them at a local fish store. But before yielding to temptation and acquiring P. lineatus for your tank, it’s important to be aware of some key facts with respect to its growth potential, social behavior, and defensive capability. So, let’s take a closer look at these and other characteristics exhibited by this species.Coral cats and CJS The coral catfish, aka the striped eel catfish or saltwater catfish, is one of several fish species available in the marine aquarium trade that exhibit what I (as of this morning) like to call Cute-Juvenile Syndrome, or CJS.