Fish tank setup: freshwater equipment in order →
How to set up a new fish tank in order: stand, tank, substrate, water, filter, heater and light, then cycling before fish.
Aquarium guides for setup and upkeep
Start with the job in front of you. Each guide leads to the measurements, exact equipment or next check you need.
Plan and set up
Fish tank stand and lid fit: what to measure →
How to choose a stand that carries your tank’s full weight and a lid that fits your exact tank, with room for the filter and light.
Freshwater aquarium equipment checklist: what to buy →
What to buy for a freshwater tank: what you need before filling, what depends on your fish and plants, and what can wait.
Fish tank decorations: fit, substrate and cleaning →
How deep to make the substrate, which decor is safe, and how to arrange it so you can still clean the glass, filter and heater.
Beginner planted aquarium equipment checklist →
What an easy planted tank needs: the right plants, a light that spans the tank, substrate, and fertilizer or CO₂ only when you need them.
Choose equipment
Aquarium filter types: sponge, HOB or canister →
Sponge, hang-on-back or canister: where each filter sits, how you clean it, and what to check before you choose a model.
Aquarium filter flow ratings: compare like with like →
Pump output, circulation and maximum flow: what each filter rating means and which to compare.
Aquarium heater sizing: use the manufacturer’s chart →
Choose heater wattage for your tank size, room temperature and target water temperature, then check that the heater fits.
Planted aquarium lighting: fit, controls and output →
How to check an LED fits your tank and lid, which controls it needs, and how to read its output for plants.
Aquarium electrical setup: dry connections and drip loops →
How to plug in aquarium equipment safely: GFCI outlets, drip loops, where the power strip goes and what to do if a plug gets wet.
Canister filter cabinet clearance: what to measure →
What to measure before a canister filter goes in a cabinet: the door opening, the space inside, the hoses and room to lift the media out.
Aquarium starter kit or separate components? →
Kit or separate parts: what kits leave out, whether you can get replacement parts, and how to compare the first-year cost.
Sponge filter setup: pump, airline and backflow checks →
What a sponge filter needs: air pump, airline, check valve and sponge, how to set them up, and how battery backup fits in.
Aquarium filter media: mechanical, biological and chemical →
Learn what foam, biological media and carbon do, where they belong in your filter, and how to care for them.
Test and prepare water
Aquarium water testing: what each kit measures →
Which tests the API Master kit and other kits include, what GH and KH add, and how to read and log your results.
Aquarium cycling: measurements before adding fish →
Use daily ammonia, nitrite and nitrate readings to judge aquarium cycling progress, know when to wait, and check what changed if readings rise again.
Aquarium salt: when to use it and how much per gallon →
How much aquarium salt per gallon the API label gives, when salt helps a freshwater tank, which fish, shrimp and plants it harms, and why it only goes in with water changes.
Maintain and troubleshoot
How to choose aquarium water change tools →
Which siphon, bucket or water changer suits your tank, and how to plan the route from tank to sink or drain.
Aquarium filter maintenance: media, access and restart →
How to clean a canister or HOB filter without killing the bacteria: what to rinse, what to replace and how to restart it.
Aquarium power-outage plan: prepare the backup air equipment →
How to keep fish safe in a power outage: a battery air pump, keeping the water warm or cool, and what to do when the power returns.
Quiet aquarium planning: equipment noise and service checks →
How to make a tank quieter: filter, air pump and heater noise and what fixes it.
Aquarium equipment troubleshooting by symptom →
What to check when a filter stops, rattles or leaks or a heater won’t hold temperature, and when to stop and contact the maker.
How to clean a fish tank: a water-change checklist →
How to clean a fish tank step by step: how much water to change, when to unplug the heater, cleaning the filter and refilling.
Used aquarium equipment inspection checklist →
What to check before you buy used tanks, filters, heaters and lights: the model, damage, missing parts, a leak test and cleaning.
Low-maintenance aquarium equipment: compare the work →
Which filters and setups mean the least work: media you can reach, reusable sponges instead of cartridges, and an easy restart.
White worms in the tank: detritus worms and what they mean →
Thin white worms wriggling in the water or the gravel are usually harmless detritus worms. Why they boom and how to cut them back.
Planaria in the tank: flatworms and how to get rid of them →
How to tell planaria from harmless worms, why they matter in shrimp tanks, and how to reduce them.
Hydra in the aquarium: tiny tentacled polyps on the glass →
What the small tentacled creatures on the glass are, why they matter for fry and shrimplets, and how to remove them.
Pest snails: bladder, ramshorn and trumpet snails →
Why small snails suddenly fill a tank, which kinds they are, and how to keep their numbers down without harming fish.
Cloudy aquarium water: white, green or brown, and the fix →
What white, green and brown cloudy water each mean in a fish tank, and what clears each one.
Why does my fish tank smell? Causes and fixes →
A healthy tank smells faintly earthy. What a rotten-egg, fishy or swampy smell means and what to check first.
Mulm in an aquarium: the brown sludge and how much to remove →
What the brown sludge in the gravel and filter is, when it helps plants and when it raises nitrate, and how to keep it in check.
Feed your fish
What do aquarium fish eat? Food types compared →
Flakes, pellets, wafers, frozen, live and freeze-dried foods: what each suits and how to build a varied diet for your fish.
How often to feed aquarium fish, and how much →
Once or twice a day, what fits in a couple of minutes, and the food's own label: how much to feed fish and the signs you are overfeeding.
What to feed a betta, and how often →
Betta pellets as the staple, frozen bloodworm and brine shrimp as treats, and how much to feed: the food's label, the fish's size and what it finishes.
What to feed goldfish →
Sinking goldfish pellets, blanched peas and greens, and frozen foods: a varied goldfish diet, and how much to feed.
Feeding fry: first foods for baby fish →
Infusoria, powdered foods, microworms and baby brine shrimp: what newly hatched and newborn fish can eat, and how often.
How to hatch baby brine shrimp for fish →
Salt water, light, air and warmth: how to hatch brine shrimp eggs for fry and small fish, and how to harvest them.
Microworms: how to culture them for fish fry →
How to start and keep a microworm culture on oatmeal and yeast, harvest the worms and feed them to fry.
Vinegar eels: a live food culture for the smallest fry →
How to culture vinegar eels in apple cider vinegar, separate them from the vinegar and feed them to fry.
Daphnia: how to culture water fleas for fish food →
How to grow daphnia in a tub of green water, feed the culture, harvest it and feed the fleas to fish.
What do aquarium shrimp eat? Feeding cherry and dwarf shrimp →
What cherry, amano and other dwarf shrimp eat in a tank, how much and how often to feed them, and why overfeeding is the usual mistake.
Grow plants
Low-tech planted tank: plants without CO₂ →
How to grow a planted aquarium with modest light, no injected CO₂ and little fertilizer: which plants, how much light, and what to expect.
Aquarium fertilizer and root tabs: what to dose and how much →
Liquid fertilizer for plants that feed from the water, root tabs for swords and crypts: the label doses side by side, how many tabs, and how to tell too little from too much.
CO₂ for planted tanks: do you need it? →
What injected CO₂ does, when a planted tank needs it, the kit involved and how to keep fish safe.
Aquarium plant melt: why new plants lose leaves →
Why crypts, swords and other new plants melt after planting, and what to do while they regrow.
How to attach java fern, anubias and moss to wood or rock →
Tie or glue rhizome plants and mosses to driftwood and stone so they root on and never rot in the gravel.
Growing aquarium moss: java, Christmas and flame moss →
How to grow moss on wood, rock or mesh, how much light it wants, how to trim it and keep it clean.
Aquarium carpet plants: how to grow a lawn in your tank →
Which plants form a carpet, what light, CO₂ and substrate they need, and how to plant them so they spread.
The dry start method: grow a carpet before you fill the tank →
How to grow carpet plants in a damp, covered tank for a few weeks before flooding it, and when to fill.
Trimming aquarium plants: stems, rosettes, rhizomes, carpets →
Where to cut each kind of aquarium plant so it grows bushier, and what to do with the cuttings.
Propagating aquarium plants: cuttings, runners and rhizomes →
How each kind of aquarium plant makes new plants, and how to split them to fill a tank for free.
Aquarium plant deficiencies: read the leaves →
Yellow old leaves, yellow new leaves, pinholes or pale patches: what each sign usually means and what to change.
Best plants for a betta tank →
Soft, easy plants that give a betta places to rest near the surface, hide and build a bubble nest.
Best plants for a shrimp tank →
Mosses and fine-leaved plants that feed and shelter cherry shrimp and their young, without CO₂.
Aquascaping styles: nature, Dutch, Iwagumi, jungle, biotope →
The main planted-tank styles, what each looks like, which plants and stones it uses and how much work it takes.
Floating aquarium plants: frogbit, salvinia and more →
Which floating plants suit a home tank, how much of the surface to cover, and how to keep them from shading out the plants below.
Low-light aquarium plants that grow under a basic tank light →
Plants that grow under the light that came with the tank and without CO₂, where each one goes, and which plants need more light.
Plants for goldfish tanks: what survives grazing and digging →
Tough, cool-water plants that survive goldfish grazing and digging, and how to plant them so they stay put.
Tissue culture aquarium plants: the cup, gel and planting →
Why lab-grown plants in cups arrive free of snails and pests, why they melt a little, and how to split and plant them.
How to plant aquarium plants: stems, rosettes and rhizomes →
Where each kind of aquarium plant goes and how deep: stem plants, rosette plants, rhizome plants, bulbs and carpets.
How long to leave aquarium lights on: fish, plants and algae →
How many hours a day to run an aquarium light: 6 to 8 to start, 8 to 10 for most planted tanks, and what to change first when algae takes off.
Red aquarium plants: which stay red and what keeps them red →
Which aquarium plants stay red under a basic light, which only color up under a strong one, and why a red plant turns green in your tank.
Planted tank substrate: aqua soil, sand or gravel →
Which substrate grows aquarium plants: volcanic soil such as Fluval Stratum, mineral gravel such as Eco-Planted or Flourite, or sand and gravel with root tabs.
Foreground, midground and background aquarium plants →
Which aquarium plants go at the front, in the middle and at the back, how tall each one grows, and how to pick back-row plants for your tank’s height.
Emersed and submersed aquarium plants: why the leaves change →
Why most potted aquarium plants are grown above water, what happens to their leaves once they are under water, and how to grow plants emersed yourself.
Breed fish
Breeding livebearers: guppies, platies, mollies, swordtails →
How livebearers breed, how to tell a pregnant female, and how to save the fry from being eaten.
Breeding cherry shrimp →
Stable water, moss and no fish that eat shrimplets: how cherry shrimp breed in a home aquarium and how to grow the colony.
Breeding bettas: what is involved →
Bubble nests, conditioning, the spawning embrace and raising hundreds of fry: what breeding bettas takes before you start.
Breeding egg scatterers: tetras, danios, barbs and rasboras →
How to get egg-scattering fish to spawn, keep the parents from eating the eggs, hatch them and feed the fry.
Breeding corydoras: spawning, eggs and raising the fry →
How cory catfish spawn, what sets them off, how to save the eggs on the glass and what to feed the fry.
Breeding cichlids: convicts, kribensis, rams and angelfish →
How pairs of convicts, kribensis, rams and angelfish breed, how both parents guard the eggs and fry, and what to plan for before they spawn.
Raising fish fry: breeder boxes, grow-out tanks, clean water →
Where to keep baby fish, how breeder boxes and grow-out tanks compare, how often to change their water and when the fry can join the main tank.
Holidays, moves, heat and cold
Going on vacation: fish care while you are away →
How long fish can go without food, what to do before you leave, and when you need a sitter.
Moving an aquarium: fish, filter and tank →
How to move a fish tank across town: bag the fish, keep the filter media wet, drain the tank completely and set it up again.
Keeping an aquarium cool in summer →
Why warm water stresses fish, how to cool a tank in a heat wave and when to act.
Bringing new fish home: transport and acclimating them →
How to carry fish home, float and acclimate them, when to drip acclimate, and how to release them without the shop’s water.
Keeping an aquarium warm in winter and through a power cut →
How to keep a tropical tank warm in a cold room, what to check on the heater before winter, and how to slow the cooling when the power goes out.