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.
337 answers in Grooming & Daily Care — page 13 of 15
Goldfish typically need 25 to 50 percent of their tank water replaced every week, with larger or more heavily stocked tanks sitting at the upper end of that range. Siphon the replacement share out while vacuuming waste from the gravel, then refill slowly with dechlorinated water matched closely to the tank…
The safest tank mates for fancy goldfish are other fancy goldfish of a similar size and swimming grade — round-bodied, double-tailed fish that cruise at the same slow pace and cannot bully the weakest fish away from food. Keep fancy varieties together rather than mixing them with fast, single-tailed commons, comets or…
They are two steps in the nitrogen cycle, and one is far more dangerous than the other. Fish waste produces ammonia, which filter bacteria convert into nitrite — a compound that blocks the blood's ability to carry oxygen and can poison fish even at low levels, so in an established tank it should always test at zero.…
pH measures how acidic or alkaline water is, on a scale from 0 to 14, with 7 neutral, readings below 7 acidic, and readings above 7 alkaline. Many common tropical fish do well in a range of about 6.5 to 7.5, close to neutral, though each species has its own preferred band within or beyond that span. Stability matters…
Ammonia is a waste poison that builds up from fish waste, uneaten food, and decaying matter. It burns and damages gills so fish cannot breathe properly, irritates skin, suppresses the immune system, and leaves fish open to infections they would normally fight off; fish may gasp at the surface, clamp their fins, stop…
Sexing a goldfish is easiest in the breeding season, when a mature male develops small white bumps, called breeding tubercles, on his gill covers and the front edge of his pectoral fins, and he looks slimmer than a female. A mature female in season looks rounder and fuller through the belly, and her vent protrudes…
Build the deepest part of a goldfish pond to about 80 cm to 1 m (about 32 to 40 inches) in a climate with hard frosts, so that zone stays below the frost line and never freezes solid. In milder areas a somewhat shallower pond can work, while colder regions call for the deeper end of that range. Keep a small ice-free…
Not as a lasting setup. Goldfish can be kept cold, because they are a cold-water fish, but they produce heavy waste for their size, and without a filter there is no colony of helpful bacteria turning ammonia from that waste into safer compounds. In a filterless tank ammonia climbs between water changes, gills burn,…
In cold weather, bottom-sitting is usually normal: goldfish slow down as the water cools, rest in the deepest, stable water, and barely eat. In warm weather it needs checking, because heat, low oxygen, ammonia from decaying waste and uneaten food, or illness can all park a goldfish on the pond floor. Look at the pond…
A bubble nest is breeding behaviour, not a puzzle or a problem. A mature male betta blows saliva-coated bubbles at the surface and gathers them into a raft, because in the wild that raft would hold fertilised eggs after spawning, guarded and tended by the father. Building one shows your betta is mature and responding…
A betta on the bottom may simply be resting, especially a long-finned or older fish, but bottom-sitting is also how bettas respond to cold water, poor water quality, exhaustion from a strong filter current, digestive trouble, or illness. Work in order: check the temperature is in the warm tropical range bettas need,…
Ragged fins on a betta usually come from one of four causes: fin rot in poor-quality water, where edges look darkened and keep shrinking; the betta biting its own long fins, which leaves clean, U-shaped notches; nippy tankmates snapping at trailing fins; or tears from sharp plastic plants, rough ornaments, or a strong…
Goldfish need a big aquarium because they do not stay the tiny fish you bring home. A fancy goldfish commonly reaches six to eight inches, a single-tailed common or comet can pass a foot, and all of them produce heavy waste that quickly turns a small volume of water high in ammonia. More water dilutes that waste…
Betta fish fight because males are fiercely territorial and have been bred for generations to defend a small patch of water against rivals. Two males put together will flare, circle, and bite until one is badly injured or killed, and a male will attack other colourful, long-finned fish he reads as competition. This is…
Keep a betta's water between about 78 and 80 degrees Fahrenheit, which is roughly 25 to 27 degrees Celsius, and keep it steady. Bettas are tropical fish, and water at typical room temperature is usually several degrees too cool and swings with the weather, so most tanks need a small adjustable heater. Check the…
Give a betta at least a 5-gallon tank, with 10 gallons an easier, more stable home that gives this fish real swimming room. Size alone is not the whole answer: the tank also needs a gentle filter, a heater holding the water around the high seventies Fahrenheit, a secure lid because bettas jump, and planting or decor…
Goldfish suit smooth, sturdy, open decorations: rounded river rocks, smooth bogwood, terracotta pots on their sides, silk plants, and tough live plants such as anubias and java fern attached to wood or stone. Everything must pass the goldfish tests — no sharp edges, because fancy varieties tear fins and damage…
Healthy goldfish poop is usually a solid brown or greenish-brown strand, often tinted by whatever the fish has been eating — green after peas or algae, reddish after colour-rich foods. It should break apart fairly soon rather than trail endlessly from the fish. Long, thin, white or clear stringy strands, especially…
Yes — goldfish are social fish who do best with their own kind, so a pair or small group is the natural setup, provided the tank is sized for it. Two goldfish produce roughly double the waste of one, so a pair needs a generously sized, well-filtered tank: fancy goldfish are commonly kept at around twenty gallons for…
A betta kept properly in a heated, filtered tank of around 20 to 40 litres typically costs about 15 to 35 dollars a month to run, once the tank itself is bought. Food and water conditioner are only a few dollars each, electricity for the small heater, filter and light is the steadiest cost, and filter media, test…
A healthy adult goldfish in a mature, filtered tank can typically go about seven to ten days without food without harm, and up to around two weeks is the outer limit most keepers plan against, not a target. Young, growing goldfish should not miss more than two to three days, and sick or underweight fish should not be…
Start with a tank of five gallons or more, a gentle filter and a heater holding the water in the high seventies Fahrenheit, because a betta is a tropical fish and plants sulk in cold, swinging temperatures. Add a fine nutrient substrate or capped soil, six to eight hours of light a day, and forgiving plants such as…
Give a betta things to explore, patrol, and rest on: live or soft silk plants, a floating log or leaf hammock near the surface, and hiding spots at different depths. Rearrange a piece of decor at water changes, float a clean ping-pong ball for short play, and offer live or frozen foods a few times a week so feeding…
A goldfish does not grow to fit its tank — it grows to its genetic size if the water stays clean enough to let it. Fancy types such as fantails and orandas typically reach 6 to 8 inches of body, while single-tailed commons, comets, and shubunkins commonly reach 10 to 12 inches or more and really belong in large tanks…
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