3,895 answers about fish & aquatics
A healthy aquarium is a balanced one — water chemistry, filtration, stocking and feeding all work together, and most fish problems start with the water. This page gathers the fish and aquatics library of KinsLe Answers in one place, organized by topic for freshwater and saltwater keepers alike. Every answer is original, written by KinsLe, and tied to a real KinsLe feature.
649 answers in Home & Lifestyle — page 16 of 28
Rummy nose tetras suit water at 77 to 82 degrees Fahrenheit and a pH between 5.5 and 6.5, warm, soft, and acidic like the lower Rio Negro blackwater they come from. They are unusually honest water-quality indicators in the tetra family: when conditions drift, the famous red nose pales before any other sign appears.…
Rosy barbs suit water at 70 to 76 degrees Fahrenheit and a pH between 6.0 and 7.5, a hardy spread reflecting the rivers and ponds of northern India they come from. They tolerate warmer water but hold their famous rosy-gold color and calmer temper at the cooler end, especially in a proper school. Splitting this active…
Odessa barbs suit water at 68 to 74 degrees Fahrenheit and a pH between 6.5 and 7.5, and the cool end of that range is where the males produce the intense red that made the species famous. From ponds and streams around Mandalay in Myanmar, they are a subtropical fish often cooked by mistake in hot tropical tanks.…
Leopard danios suit water at 68 to 74 degrees Fahrenheit and a pH between 6.5 and 7.5, thriving in the cool, moving water their danio ancestors evolved in across Asian hill streams. They tolerate warmer tanks but grow restless and short-lived in them, so a standard hot tropical setup is the main thing to avoid. Before…
Lemon tetras suit water at 76 to 80 degrees Fahrenheit and a pH between 6.0 and 7.0, warm and slightly acidic like the Tapajos River tributaries in Brazil where they originate. This is a fish whose beauty is conditional: the lemon-yellow fins and red eye appear only in soft, settled water, while in hard alkaline tanks…
Gold barbs suit water at 70 to 76 degrees Fahrenheit and a pH anywhere between 6.0 and 8.0, making them a notably adaptable fish for a community tank. Bred from the green barb of southern China, they actually prefer the cooler end of the tropical range and stay more active and longer-lived there than in a hot tank.…
Glowlight tetras suit water at 75 to 80 degrees Fahrenheit and a pH between 6.0 and 6.5, in soft water recalling the blackwater rivers of Guyana. Their orange-gold stripe lights up in dim, acidic conditions and washes out in bright, alkaline tanks, so water chemistry is half the display with this species. Keeping the…
Ember tetras suit water at 75 to 80 degrees Fahrenheit and a pH between 5.5 and 7.0, in soft water like the slow Brazilian streams they come from. At barely an inch long, embers feel every swing in a small tank, so the real skill is changing water in small, matched amounts rather than large weekly pours. If a reading…
Congo tetras suit water at 76 to 81 degrees Fahrenheit and a pH between 6.0 and 7.0, slightly acidic to match the Congo River basin they come from. This is one of the largest tetras commonly kept, and males develop flowing fins and iridescent color only when the water stays warm, clean, and steady. Sharing the tank's…
Celestial pearl danios suit water at 72 to 75 degrees Fahrenheit and a pH between 6.5 and 7.5, running cooler and a touch more alkaline than most tropical nano fish. These tiny fish come from shallow, plant-choked ponds in Myanmar, so a standard tropical heater setting of 80 degrees is too warm and shortens their…
Cardinal tetras suit water at 75 to 78 degrees Fahrenheit and a pH between 5.0 and 6.2, in soft water that mimics the blackwater streams of the upper Orinoco and Rio Negro. Unlike hardier tetras, cardinals genuinely struggle in alkaline tap water, so test before you buy and plan on softening the water if your supply…
Black skirt tetras suit water at 75 to 80 degrees Fahrenheit and a pH between 6.0 and 7.5, and this deep-bodied South American tetra is forgiving anywhere inside that window. Keep the school at the warmer middle of the range if tankmates are other tropical community fish, and avoid letting a cold room drag the tank…
White cloud mountain minnows are coldwater fish that thrive in unheated water between about 57 and 72°F, so their tank mates must pass a temperature test before a temperament one: gold barbs, zebra and leopard danios, butterfly loaches, rosy barbs in a roomy tank and cherry shrimp all enjoy the same cool conditions.…
Tiger barbs are the most famous fin-nippers in the hobby, and the whole strategy for keeping them is the school: in a group of eight to ten or more, their endless sparring stays inside the group and other fish are largely left alone. Suitable tank mates are bold, fast and short-finned, including other barbs, zebra…
Serpae tetras are deep-red, inch-and-a-half tetras with a genuine fin-nipping habit, and their tank mates must be sturdy, short-finned fish that refuse to be victims: black skirt tetras, Buenos Aires tetras, fast danios, larger rasboras, robust barbs and armoured corydoras all cope well. Angelfish, guppies, bettas and…
Rosy barbs are big, boisterous schoolers that reach four inches and prefer cooler water, so they need sturdy companions of a similar size: other barbs, zebra and giant danios, swordtails, rainbowfish, corydoras and loaches all hold their own in a rosy barb tank. Long-finned fish are the ones to leave out, because…
Leopard danios are the spotted form of the zebra danio, fast, hardy top-dwellers of about two inches, and their natural companions are fish that share their pace or stay out of its way: other danios, white cloud mountain minnows, gold and rosy barbs up top, with corydoras and weather loaches living calmly below. Slow,…
Lemon tetras are peaceful two-inch schooling fish that colour up properly only in a group of eight to ten, and they pair well with other small tetras, harlequin rasboras, pencilfish, corydoras, otocinclus and a honey gourami or a pair of apistogramma as a centrepiece. Fin-nippers such as tiger barbs and serpae tetras…
Gold barbs are hardy, active schoolers of about three inches that tolerate cooler water than most community fish, and their best companions are species that share that brisk pace: zebra and leopard danios, white cloud mountain minnows, rosy barbs, other peaceful barbs, corydoras and dojo loaches. Long-finned, slow…
Glowlight tetras are gentle, inch-and-a-half schooling fish whose ideal company is other small, quiet species: neon and cardinal tetras, harlequin rasboras, ember tetras, corydoras, otocinclus and a honey gourami all settle in beside them without friction. Fin-nipping barbs such as tigers and serpaes are the main fish…
Congo tetras are the giants of the tetra family, with males reaching three inches and growing long, flowing fins, so their tank mates need to match that scale: rainbowfish, diamond tetras, corydoras, synodontis catfish and a pair of kribensis all live beside them. Two groups fail at opposite extremes, because tiny…
Celestial pearl danios are barely an inch long and quietly shy, so their tank mates must be drawn from the same tiny weight class: chili rasboras, emerald dwarf rasboras, pygmy corydoras, otocinclus and cherry shrimp are the reliable companions. Anything big enough to fit a celestial pearl danio in its mouth…
Cardinal tetras are small, wholly peaceful schooling fish, and their safest companions are other gentle soft-water species: neon tetras, rummy-nose tetras, ember tetras, pygmy corydoras, otocinclus catfish and cherry shrimp all share their world comfortably. Anything large enough to swallow a one-inch fish rules…
Black skirt tetras do best alongside other calm, short-finned community fish: corydoras catfish cruising the bottom, neon or rummy-nose tetras, platies, and a honey gourami all work well. What you want to avoid is anything slow with long, flowing fins, because bettas and guppies are prime targets for this species'…
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