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.
562 answers in Choosing & Adopting — page 20 of 24
Yes, guppies need a heater in most homes, because these tropical livebearers do best around 24 to 26 degrees and lose colour, condition and breeding vigour in cool, swinging water. Fit an adjustable heater and a thermometer, and place the tank where room temperature does not fight the heater at night. Share the target…
No, goldfish do not need a heater — they are cool-water fish that thrive around 18 to 22 degrees and become stressed in water kept tropically warm. Your job is the opposite of heating: keep the tank away from radiators and sun, and hold a steady cool temperature rather than chasing a warm one. Note the cool range in…
Usually yes: most commonly sold corydoras are warm-water fish happiest around 22 to 26 degrees, and a heater keeps the cool bottom layer from dipping below that in a typical home. A few species prefer the cooler end, so match the heater setting to the exact corydoras you keep rather than the tank average. Split the…
Yes, a betta needs a heater unless the room itself holds the water steadily around 24 to 27 degrees day and night. Small betta tanks lose heat fastest and swing widest, which is why an unheated bowl leaves a betta sluggish, faded and prone to illness. Use a small adjustable heater with a thermometer, and hand the…
Yes, angelfish need a heater in almost every home, because these Amazon cichlids live best in warm water around 24 to 28 degrees that room temperature rarely holds. Choose a heater sized for the full tank, pair it with a separate thermometer you trust, and guard against slow overnight drops in a cool room. Write the…
Yes, zebra danios are peaceful in intent but boisterous in effect, so they suit communities built from other brisk, short-finned fish. Keep a proper school so their chasing stays inside the group, and avoid pairing them with slow, long-finned fish whose fins and food they will monopolise. A good local shop found…
Yes, zebra danios are genuinely hardy, tolerating cooler water and small beginner mistakes better than most small tropical fish. Hardy does not mean cycle-proof, so still mature the filter before stocking, keep six or more together, and hold the temperature steady rather than letting the tank swing between cold nights…
Yes, zebra danios are one of the most forgiving first fish if you give them length to swim and company of their own kind. Keep at least six together in a long tank of about 75 litres or more, add a tight lid because they jump, and feed small meals they can finish quickly at the surface. Record the school size, tank…
Swordtails are peaceful toward other species and mix safely with most community fish of similar or larger size, but they are boisterous — their constant motion and the males' sparring can overwhelm very shy or slow tankmates. Within the species, males chase each other and court females persistently, so keep one male…
Yes — swordtails are hardy, colorful livebearers that suit beginners well, provided the first tank gives them swimming room. They grow larger than platies, reaching four to five inches with the male's namesake tail extension, and they are energetic, so twenty gallons or more with a secure lid is the sensible starting…
Mostly yes — siamese algae eaters are peaceful toward the great majority of community fish and ignore small species entirely. Two qualifications apply: an adult can squabble with fish of a similar shape and grazing habit, such as other algae eaters or shark-shaped species, and a crowded or underfed adult may rasp at…
Yes, siamese algae eaters are hardy fish that tolerate the conditions of a typical first tank well — a broad temperature range, ordinary tap-water chemistry, and the occasional slightly late water change included. Their hardiness has one precondition — room: a true siamese algae eater grows to five or six inches and…
Siamese algae eaters are excellent at their job and hardy, but they suit beginners only if the first tank is big enough — this is the deciding factor. A true siamese algae eater grows to five or six inches, swims restlessly, and does best in a tank of forty gallons or more, so it is a poor fit for the small starter…
Yes, platies are thoroughly peaceful community fish that mix safely with the great majority of small, calm species — tetras, rasboras, corydoras, guppies, and dwarf shrimp included. Their only social wrinkle is internal: males court females persistently, so a lone female in a group will be harassed, and a ratio of two…
Platies are close to the ideal beginner fish: hardy, colorful, active, and forgiving of the small water-chemistry wobbles every new keeper has. They suit a tank of ten gallons or more, eat almost anything offered, and get along with most peaceful community species. The one thing to plan for is that platies are…
Yes — pearl gouramis have a notably peaceful temperament and make serene community fish. A pearl will cruise the upper water without troubling small tetras, rasboras, or bottom-dwellers, and even males are only mildly territorial toward other gouramis rather than aggressive. The cautions are about companions, not the…
Yes, pearl gouramis are genuinely hardy — among the toughest of the gouramis and well suited to a first tank of thirty gallons or more. Their labyrinth organ lets them breathe surface air, they accept a broad range of ordinary water conditions, and they eat readily, all of which forgives the wobbles of a keeper still…
Yes — pearl gouramis are one of the best larger fish a beginner can choose, combining real hardiness with a calm temperament and genuinely beautiful patterning. They grow to around four or five inches, so they ask for a tank of thirty gallons or more rather than a small desktop setup, and they appreciate planted cover…
Completely — otocinclus are among the most peaceful fish in the hobby, with no aggression toward tankmates of any kind. The real question runs the other way: an oto community works only when the other residents leave the otos alone, because these small catfish cannot compete at feeding time and can be bullied or even…
Yes, with one honest caveat: otocinclus are gentle, tireless algae grazers that suit a beginner well once the tank itself is established and stable. These tiny schooling catfish need a group of six or more, soft algae to graze, and water that does not swing, so a brand-new aquarium that is still cycling is the one…
Yes — neon tetras are perfectly peaceful, bothering no one, never nipping fins and spending their day drifting in a loose, glittering school. Their problem is the opposite one: at barely an inch long they are a natural mouthful for angelfish and any other fish that hunts small prey, so their safety is decided entirely…
Yes — but not on the first day, and that timing is the difference between success and a sad first month. Neon tetras are small, peaceful and inexpensive, yet they are genuinely sensitive to the ammonia swings and unstable chemistry of a brand-new aquarium. Add a school of ten or more only after the tank has run mature…
Mostly, yes: mollies rarely trouble other species and mix happily with fish of a similar size and tempo. The friction is internal, because males chase females persistently and spar with rival males, and a crowded, underfed group may pester slow, long-finned tankmates. Space, a surplus of females and broken sightlines…
Yes — mollies are active, hardy and unfussy about food, which is why shops recommend them to beginners, but they come with conditions. They grow to around four inches and want a roomy tank, hard alkaline water, and more females than males so the males' constant attention is spread out. Above all, mixed sexes mean fry,…
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