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 1 of 28
Make the tank safe for a small celestial pearl danio by covering every gap in the lid around cables and equipment, and by fitting a fine sponge pre-filter or mesh guard over the filter inlet so a fish barely an inch long cannot be drawn in or slip through. Juveniles and even adults of this species can wedge into…
A celestial pearl danio stays healthiest in water kept steadily in the low-to-mid seventies Fahrenheit, roughly seventy-three to seventy-nine degrees, without daily swings. This species comes from cool, shallow, plant-filled ponds, so it tolerates the lower end of that range well and suffers more from heat and…
An adult celestial pearl danio needs a tank of at least ten gallons for a proper group, even though a single fish is barely an inch long, because this species lives as a shoal and behaves naturally only with company and swimming room. A twenty-gallon long tank is kinder still, giving males space to display without…
A pearl gourami stays healthy in warm water held around 77 to 82 degrees Fahrenheit, with steadiness valued more than any single point in that band. Keep a fitted lid on the tank, because this labyrinth fish breathes surface air and cold air above cool-feeling water can chill it even when the thermometer reads fine.…
An adult pearl gourami needs a tank of about 30 gallons as a sensible minimum, with a long footprint preferred over a tall one. This fish grows to around four or five inches, cruises the middle and upper water, and needs horizontal room to patrol plus calm surface space where it can breathe air and, for males, tend a…
A kuhli loach stays healthiest in warm, steady water, with most keepers holding the tank around 76 to 82 degrees Fahrenheit and avoiding sudden swings rather than chasing one exact number. Use a dependable heater and read a thermometer placed away from it daily, because a loach resting on the substrate feels the…
Keep a group of adult kuhli loaches in at least a 20-gallon long tank, because these eel-like bottom dwellers need floor space, a soft substrate to sift, and room for the group they live in. A smaller footprint crams several shy loaches into too little hiding territory, even though each fish looks small. Prioritize…
A harlequin rasbora needs warm tropical water, roughly 72 to 79 degrees Fahrenheit, kept steady with a reliable heater and a thermometer you check daily. Unlike cooler-water fish, this rasbora loses appetite and color when the tank drifts into the high 60s, especially overnight. Keep the heater sized to the tank and…
Plan on at least a 10-gallon tank for a small school of adult harlequin rasboras, with a 20-gallon long tank the kinder minimum if you want natural shoaling and stable water. Rasboras are group fish, so the tank must fit the school, not a single fish, and length matters more than height for their back-and-forth…
A zebra danio stays healthiest in cool to mild water, roughly 64 to 75 degrees Fahrenheit, with stability mattering more than chasing one exact number. Keep the tank away from sunny windows and check a thermometer placed away from the heater each day, because danios react quickly to swings after water changes. Match…
An adult zebra danio needs a tank of at least 10 gallons, but length matters far more than volume for this fish, so choose a longer tank rather than a tall or cube-shaped one. Zebra danios are nonstop swimmers that race in loose groups, and an adult group of at least six needs a clear swimming lane to behave normally.…
A bristlenose pleco stays healthy in water between about 73 and 81 degrees Fahrenheit, and it handles that range comfortably as long as changes arrive slowly. Keep a dependable heater and a separate thermometer on the tank, since a pleco glued to the glass near a failing heater feels every drift first at the bottom.…
An adult bristlenose pleco needs a tank of at least 30 gallons, with bottom area mattering most because this fish grazes, rests, and claims its cave along the floor. A single adult fits that minimum comfortably, especially with a piece of driftwood to rasp on and a cave it can call its own. Add a second adult —…
Keep a fitted lid on the tank and lower the waterline a little, because a small corydoras catfish darts to the surface for air and can leap through a rim gap on a startled jump. Wrap the filter inlet in a fine sponge pre-filter or fit a smooth intake guard, since a young fish resting near an exposed intake can be…
Most commonly kept corydoras catfish stay healthy in water between about 72 and 78 degrees Fahrenheit, with steady conditions mattering more than chasing one exact number. A few species prefer the cooler end of that band, so confirm where your particular corydoras sits before setting the heater. Use a reliable heater…
An adult corydoras catfish needs a tank of at least 20 gallons, and because corydoras are schooling fish, that minimum really means room for a group of at least six adults, not a single fish alone. Floor space matters more than height for these bottom dwellers, so a longer 20-gallon footprint beats a tall, narrow tank…
Fit a snug lid with no gap wider than the small angelfish's body, and cut any notches for cords and tubing tight so the fish cannot slip out while chasing food at the surface. Cover the filter inlet with a fine sponge pre-filter or a mesh guard, because a small angelfish's long, soft fins can be pulled against an…
An adult angelfish needs a tank of at least 29 gallons, and height matters as much as floor space because a grown fish carries tall, deep fins and a body that can reach six inches long with much longer fin span. A taller tank around eighteen inches high or more lets an angelfish hold its fins fully open without…
A guppy needs warm water held steadily around 74 to 82 degrees Fahrenheit, with the middle of that range a good everyday target. Guppies are tropical livebearers, and water that repeatedly dips into the sixties leaves them clamped, inactive and prone to sickness, while heat well above the range speeds breeding and…
A small group of adult guppies needs a tank of at least ten gallons, because guppies are kept socially rather than alone and breed readily, quickly raising the stocking level. Ten gallons gives males room to display without harassing females relentlessly and gives fry scattered cover instead of none. A longer tank…
Fit a secure, full lid with the gaps around cords and pipes closed, and cover the filter inlet with a sponge pre-filter or guard so a small goldfish cannot be pinned against the slots or drawn in. Goldfish explore with their mouths and rest near intakes, so spread the suction over a wide foam surface and check fins…
A goldfish stays healthy in cool water, roughly 65 to 75 degrees Fahrenheit, with fancy varieties happiest toward the upper part of that range and away from sharp swings. Goldfish do not need a tropical heater in a normal heated home, but they do suffer in a tank warmed by sun, lights or a hot room well into the high…
A single adult fancy goldfish needs at least twenty gallons, a long-bodied common or comet goldfish needs considerably more, and each additional fancy goldfish needs roughly another ten gallons. Goldfish grow large, produce heavy waste and use the length of a tank for steady swimming, so a long footprint matters more…
Cover every gap in the lid around cords and filter cut-outs, because a small betta can jump through a surprisingly narrow opening, and fit a sponge pre-filter or fine guard over the filter inlet so fins and body cannot be pulled against it. Check that the outflow does not shove the betta across the tank, and run a…
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