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 9 of 28
Sand or smooth, rounded gravel suits a bristlenose pleco best, because this fish spends nearly its whole life in contact with the floor — grazing across it, resting on it, and shuffling over it after dark. Sharp gravel can scrape the soft underside and mouth as the pleco works a patch, so texture matters more here…
Smooth fine sand or rounded fine gravel suits a betta best, because a betta often rests low in the tank and drags long, delicate fins across the floor. Fine grains also trap less uneaten food than chunky gravel, which matters in the small, warm tanks bettas usually live in. A natural, darker colour helps a betta's own…
Fine sand or smooth, fine gravel suits an angelfish tank best, laid deep enough to root the tall plants angelfish like to drift between. Angelfish feed mostly in open water, so the substrate serves the plants, the bottom-dwelling tank mates, and the look of the tank more than the angels themselves. A darker, natural…
A group of white cloud mountain minnows needs at least a 10-gallon tank, and a 20-gallon long is a better home for an active school of eight or more. These slim, cool-water fish stay small but swim constantly through the middle and upper water, so a longer footprint matters more than extra height. Pick the larger…
A threadfin rainbowfish needs at least a 20-gallon long tank for a proper school. Males carry long, delicate trailing fins and display to each other constantly, so the school needs swimming length plus gentle flow that will not batter those fins. Keep eight to ten or more, plant the back and ends, and leave the centre…
A sparkling gourami needs at least a 10-gallon tank for a pair or small group, and a 15- to 20-gallon suits a group with several males better. These tiny croaking gouramis are peaceful overall, but males spar over plant-thick corners, so floor space divided by planting keeps the peace. Still water, floating cover, and…
A scarlet badis needs at least a 10-gallon tank for a pair or trio, with a 20-gallon long better if you want more than one male. These thumbnail-sized hunters are territorial, and each male needs his own plant-choked patch to claim. Dense planting, caves, and leaf litter break the tank into separate territories and…
A rummy-nose tetra school needs at least a 20-gallon long tank, and a 30-gallon or larger is better for the dozen-plus fish that show their famous tight schooling. Their red noses and black-and-white tails only shine when they can travel together down a length of open water. Keep the group large, the water clean and…
Rice fish need at least a 10-gallon tank for a small group, and a 20-gallon long gives a school proper room to breed and display. These hardy medaka-style fish swim at all levels, thrive in groups of six to eight or more, and also suit unheated tanks and sheltered outdoor tubs. Favour surface area and length over…
A single pea puffer needs at least a 5-gallon tank, and a group does far better in a heavily planted 20-gallon long. These tiny puffers are curious, intelligent, and territorial for their size, patrolling plants and hunting snails. One fish alone rules a 5-gallon happily; several in a small tank will squabble over…
A Norman's lampeye needs at least a 10-gallon tank, and a 20-gallon long is better for the school it deserves. These small West African fish carry a bright crescent of blue on the eye and swim in a loose group near the surface. Keep eight or more, fit a tight lid because they jump well, and favour length so the school…
A nerite snail can live in a 5-gallon tank, but a 10-gallon or larger established tank suits it better because it needs real algae and biofilm to graze. One nerite per roughly 5 gallons is a sensible guide so it does not out-eat its food supply. Fit a tight lid, since nerites climb out, and avoid a brand-new spotless…
A licorice gourami needs at least a 10-gallon tank for a pair, with a 15- to 20-gallon better for a small group. Size is only half the story for this shy blackwater fish: soft, dim, still water, leaf litter, and caves matter as much as gallons. A larger footprint lets males hold separate hiding spots and reduces…
A least killifish can live in a 5-gallon tank, but a 10-gallon planted tank is the wiser home for a growing colony. Despite the name it is a tiny livebearer, and females drop small numbers of fry over time, so numbers creep up quietly. Dense floating and stem plants give fry shelter, gentle filtration avoids pulling…
A hillstream loach needs at least a 20-gallon long tank, and a 30- to 40-gallon long is better for a small group. Floor space, strong flow, and oxygen matter far more than depth for this flat, rock-clinging fish. Fill the base with smooth rounded stones, run a filter or powerhead that keeps water moving across them,…
A fork-tail rainbowfish needs at least a 20-gallon long tank, and a 30-gallon long is kinder for a proper school. These slim rainbows stay small, but they swim fast in open water, flash their forked yellow tails at each other, and feel exposed in short tanks. Choose length over height, fit a tight lid because they…
A clown killifish needs a tank of about 5 to 10 gallons, long and low rather than tall, for a pair or small group, and the measurement that outranks all others is how completely its lid seals. These tiny surface dwellers live in the top inch of water under floating plants, jump expertly through gaps, and need calm,…
A celestial pearl danio needs a tank of about 10 gallons with a decent footprint for a group of six to ten, and 20 gallons suits a bigger group with room for males to keep out of each other's way. These are tiny fish, but males spar and display constantly, so floor space, planted cover, and broken sight lines matter…
A cardinal tetra needs a tank of about 20 gallons, ideally a long format, for a school that shows the species at its best, meaning ten or more fish rather than a token few. Single cardinals are tiny, but the school is the animal you are actually housing, and it needs planted edges, dimmer corners, and a clear lane to…
A bumblebee goby needs surprisingly little water but plenty of floor: a tank of about 10 gallons suits a small group, with 15 to 20 gallons giving each fish room to hold a tiny territory. Footprint matters more than height because these bottom perchers claim a cave, shell, or stone each and bicker over neighbours.…
A boesemani rainbowfish needs length before anything else: plan on a tank of about 55 gallons with roughly four feet of swimming length for a proper group of six or more. These are large, active schoolers once grown, with males reaching a deep-bodied size that looks cramped and washes out in short tanks. A longer,…
Zebra danios suit a long tank decorated like a stream edge: tall plants and fine greenery pushed to the back and ends, smooth rounded stones and gravel along the floor, and a completely open swimming lane through the middle and upper water. These tireless swimmers use length, not hiding spots, so decor should frame…
Siamese algae eaters suit broad-leaved plants and broad flat surfaces they can graze and rest on, such as anubias and sword plants, smooth rocks, and driftwood lengths laid along their swimming routes. These are busy, social fish that patrol the whole tank, so keep long open lanes, plant the edges, and fit a tight lid…
Pearl gouramis suit a calm, heavily planted tank with tall stem plants and vallisneria softening the back, driftwood arches to drift beneath, and floating plants covering part of the surface. Floating cover matters twice for this species: it shades a shy fish into confidence and gives a male a sheltered ceiling if he…
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