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 21 of 28
Rummy nose tetras suit calm, similar-sized tankmates that share their warm, soft water: other small tetras such as cardinals and embers, harlequin rasboras, corydoras, otocinclus and kuhli loaches all mix well. Avoid anything big enough to see a rummy nose as food — adult angelfish are the classic mistake — and skip…
Keep rummy nose tetras in a group of at least six, and choose ten or more if the tank allows — they are true schooling fish and behave quite differently in a crowd. In small numbers they hide, lose the bright red colouring on the face, and stress easily; in a proper school they move together across the tank and colour…
Direct sunlight harms an aquarium in two ways: it grows algae explosively, delivering more intense light than any tank light, and it heats the water fast, because glass and water trap warmth like a greenhouse, so a small tank can swing several degrees in an afternoon and fall back overnight. Fish are stressed by those…
Corydoras and loaches feed by pushing their faces into the substrate: corydoras sift mouthfuls through delicate barbels, the whisker-like feelers they taste food with, and sharp gravel wears those barbels down and lets infection in. Loaches such as kuhlis are scaleless and soft-bellied, so rough stones scrape skin…
Put your aquarium on a level, load-bearing stand against a wall in a quiet room, out of direct sunlight and away from radiators, air vents, and draughty doors, so its temperature stays steady and the fish are spared the vibration and sudden movement of speakers, washing machines, or a hallway the whole household…
Zebra danios suit other hardy, active fish that enjoy the same cool, fast-moving water and cannot be outcompeted or nipped: white cloud mountain minnows, other danio species, cherry barbs, and corydoras are all dependable companions. The fish to avoid are slow swimmers with long, flowing fins, such as bettas,…
A siamese algae eater suits active, peaceful community fish that can hold their own beside a busy grazer: danios, rainbowfish, peaceful barbs, and most tetras and rasboras live well with one, and it ignores bottom fish like corydoras. The cautions are flat-bodied, slow fish such as angelfish and discus, because an…
A pearl gourami suits calm, mid-sized community fish that neither nip its long trailing feelers nor compete with it for the surface: peaceful tetras of a decent size, rasboras, corydoras, and kuhli loaches all live comfortably alongside one. Avoid tiger barbs and other fin-nippers, and avoid a second male gourami of…
Neon tetras suit small, peaceful fish that cannot fit a neon in their mouths and will not chase a school: other tiny tetras, chili rasboras, corydoras, and otocinclus are classic companions, and dwarf shrimp are usually ignored. The rule is size and temperament, because anything much larger, including an angelfish,…
A mystery snail suits almost any gentle community fish that will leave its long antennae and eyes alone: small tetras, rasboras, corydoras, and peaceful livebearers all graze and swim past without bothering it. The dangers are fish that nip soft appendages or hunt snails outright, so avoid loaches that crush shells,…
A kuhli loach's best tank mates are small, peaceful fish that swim in the middle and top of the tank and never hassle the bottom, where the kuhli lives: tiny rasboras, ember tetras, and a honey gourami all work well, as do calm corydoras in modest numbers. Skip anything that nips, chases, or outcompetes, because a…
Harlequin rasboras are calm, copper-coloured schoolers that pair with almost any fish as peaceful as themselves: cherry barbs and ember tetras in the middle water, corydoras and kuhli loaches below, honey gouramis drifting above, and shrimp and snails left entirely alone. Keep the rasboras in a school of eight or more…
Guppies are friendly, busy livebearers that suit almost any peaceful community: corydoras below them, ember tetras and harlequin rasboras beside them, otocinclus on the glass, and a honey gourami as a calm centrepiece all make reliable partners. The failures come from two directions — fish that nip the males' flowing…
The best tank mates for a goldfish are, overwhelmingly, other goldfish — matched by type, because fast single-tailed commons and shubunkins will outswim and out-eat slow fancies like fantails and orandas at every meal. Beyond goldfish, the honest list is short: goldfish want cool water, produce heavy waste, and…
Corydoras are among the easiest tank mates in the hobby — peaceful, armoured bottom-dwellers that ignore other fish entirely — so the question is usually reversed: choose mid-water fish that will not bother them. Tetras, rasboras, cherry barbs, guppies, honey gouramis, and most bettas all thrive above a cory school,…
Cherry barbs are the peacemakers of the barb family — small, shy schooling fish that never developed the family habit of nipping fins — and they pair happily with other gentle community fish: harlequin rasboras, ember tetras, corydoras, kuhli loaches, otocinclus, and a honey gourami as a calm centrepiece. Keep the…
A bristlenose pleco is one of the easiest community fish to house: it is a peaceful, nocturnal grazer that suits almost any calm tank mate, from tetras, rasboras, and guppies above it to corydoras sharing its floor. Fellow bottom dwellers are fine as long as each has a cave of its own, and even a second bristlenose…
Whether a betta can have tank mates depends on the individual fish and the size of the tank, but the safest companions live at the bottom and mind their own business: corydoras, kuhli loaches, and nerite snails coexist with most bettas in tanks of ten gallons or more. Small peaceful schoolers such as ember tetras and…
Angelfish are cichlids with a graceful look and a hunter's appetite, so their best tank mates are mid-sized, calm fish that are too large to be eaten and too peaceful to provoke them: bleeding heart or diamond tetras, corydoras, a bristlenose pleco, pearl gouramis, and Bolivian rams all have long track records…
Planted tanks and bottom dwellers pull substrate in opposite directions, so the best answer is usually a deliberate combination: a nutrient-rich aquasoil where roots feed, zoned alongside fine, smooth sand where bottom dwellers rest and sift. Corydoras and loaches have delicate barbels and bellies that sharp gravel…
A second tank is easy to buy and surprisingly easy to underestimate: it doubles your water changes, your filter cleaning, and your electricity, and it needs a floor and stand that can carry serious weight — water alone runs about ten pounds per gallon once substrate and rock are in. Decide its job before you shop: a…
A guest room shrimp tank mostly needs protection from kindness and curiosity: guests spray perfume and insect repellent, open windows on cold nights, switch lights off at odd hours, and cannot resist feeding the tiny shrimp. Before guests arrive, move aerosols out of the room, set the tank light on a timer, and put…
Fumigation is dangerous for an aquarium: insecticide mist and paint fumes reach tank water through air pumps and any gap in the lid, and invertebrates and fry can die at doses fish barely survive. If the tank is small enough to carry, move it out of the home before treatment starts; for a fixed tank, switch off air…
Start with the arithmetic: water weighs about a kilogram per litre, so a big community tank plus glass, stand, substrate and rock can easily pass half a tonne concentrated on four or six small feet. Check which way the floor joists run and place the tank across them, tight against a load-bearing wall, never mid-span…
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