Fishkeeping guides for aquarists
Short, practical guides to help you keep your tank healthy. Built for fishkeeping hobbyists and everyday aquarists.
Looking for tools? Try our free stocking calculator, tank size calculator, or see our aquarium app comparison.
New to fishkeeping? Start with how to set up a fish tank, how to cycle, and first tank.
Crowd thread digests — summaries of public discussions (charts and thread scores).
Fishkeeping fundamentals for new aquarists
A practical starter framework for setup, cycling, stocking, and maintenance.
Getting startedUsing an established filter when setting up a tank
How to use a cycled filter to speed up a new setup. Transfer media safely.
Fish careThe curse of dwarf gouramis: myth vs reality
DGIV, hardiness, and how to improve your odds — or choose alternatives.
Fish careCelestial pearl danios (galaxy rasboras)
Discovery story, care, and why these nano fish are worth the attention.
Fish careOscars: keeping them and what to watch out for
Tank size, feeding, HITH, and common pitfalls for these big cichlids.
StockingNeon duels: neon vs black neon and other tetras
Compare neon, black neon, cardinal, glowlight, rummynose — and how to mix.
StockingCan angelfish live with neon tetras?
Risks, when it might work, and safer alternatives.
Plants & algaeCO2 systems in fish tanks: what you need to know
When you need it, pressurized vs DIY, and fish safety.
Fish careLoach guide: types and their role in the tank
Kuhli, clown, yo-yo, hillstream, zebra, dwarf chain — roles and tank fit.
Water & cycleHow to manage water quality with App-aquatic
Track core readings, review trends, and respond quickly before fish are stressed.
MaintenanceHow to stay on top of tank care with App-aquatic
Use reminders and logging to keep a reliable care rhythm.
StockingHow to make the right stocking decisions with App-aquatic
Use compatibility and bioload checks before adding fish.
MaintenanceOxygen stones and bubblers
What they do, when they help with oxygen, and whether you need one.
Illness & hospitalSuddenly losing fish — what to do
Step-by-step response when fish die, including when readings look fine.
Illness & hospitalWhy are my fish dying one by one?
Sequential deaths: chronic stress, disease spread, aggression. Data, causes, and actions.
Illness & hospitalInternal and external parasites in fish
Types, symptoms, chemical and natural treatment. Ich, flukes, velvet, nematodes, hexamita.
Water & cycleHow to keep your fishtank water crystal clear
Filtration, water changes, feeding, and fixing cloudy or green water.
Fish careCan you keep female bettas together?
Sorority tanks: when they work, tank size, and when to avoid.
Illness & hospitalFish flashing: causes and what to do
Why fish rub on surfaces and how to diagnose before treating.
Getting startedWhen to add plants in your cycle
Best timing for plants in new tanks and how they support stability.
MaintenanceChanging from gravel to sand
A safe substrate swap plan that protects your cycle.
MaintenanceBest sand for your aquarium
How to choose the right type of sand for fishkeeping and your tank.
Water & cycleCloudy water and bacterial bloom
Why milky water happens and how to clear it safely.
Fish careFish treats: what can you safely give your fish?
Treat ideas, feeding frequency, and foods to avoid.
StockingDo fish grow to tank size? Fact or myth
Why stunting is not healthy adaptation and what to do instead.
Getting startedImpact of fish tanks on ADHD
A practical, non-medical look at routine, focus, and calm.
InvertebratesIsopods: what they are, where they come from, should you worry
What they look like, where they come from, and whether to be worried.
Water & cycleWhat to do if your water is too acid or too alkaline
Safe ways to raise or lower pH and when to leave it alone.
Water & cycleWhat to do if your water is too hard
GH and KH explained, when it matters, and how to soften or work with your tap.
StockingGreat setups for a 20 gallon community tank
Example combinations: tetra and cory, betta community, livebearers, and more.
StockingGreat setups for a 30 gallon community tank
More room for schools and centrepieces. Example combinations that work.
StockingGreat setups for a 40 gallon community tank
Larger schools and more variety. Example peaceful community setups.
StockingHow to use a stocking calculator
Plan fish combinations, check compatibility, and avoid overstocking before you buy.
StockingGood setups for a 50 litre tank
Community, centrepiece, and nano options for ~13 gallon tanks.
StockingGood setups for a 60 litre tank
Community and centrepiece options for ~16 gallon tanks.
StockingGood setups for a 100 litre tank
Community, centrepiece, and dwarf cichlid options for ~26 gallon tanks.
StockingGood setups for a 50 gallon tank
Community, centrepiece, and cichlid options for ~190 litre tanks.
StockingGood setups for a 75 gallon tank
Community, centrepiece, and cichlid options for ~284 litre tanks.
StockingGood setups for a 100 gallon tank
Community, centrepiece, and cichlid options for ~380 litre tanks.
StockingGood setups for a 200 litre tank
Community, centrepiece, and cichlid options for ~53 gallon tanks.
StockingGood setups for a 300 litre tank
Community, centrepiece, and cichlid options for ~80 gallon tanks.
MaintenanceWhat to do when moving house (with an aquarium)
Plan the move: keep fish safe, save your cycle, and set up again without disaster.
MaintenanceAquarium care on holiday: do’s, don’ts, and how to prepare
Going away? Feeding, fish sitters, automatic feeders, and the mistakes that cost fish their lives.
MaintenanceCrystals in fish tanks: what’s safe and what isn’t
Rose quartz: yes. Pyrite: absolutely not. The complete guide to aquarium-safe crystals.
Getting startedHow much does it really cost to set up a fish tank?
Budget, mid-range, and premium breakdowns — with prices for UK, US, Europe, Canada, Australia, and NZ.
StockingCentrepiece fish: how to choose the perfect showpiece for your tank
Popular, bizarre, and rare options — and what to consider before picking one.
Plants & algaeHow to get rid of hair algae in your aquarium
Causes, manual removal, and why Amano shrimp are the single best biological weapon against it.
Fish careDoes fish food expire? What actually happens after the best-before date
Vitamins degrade, oils go rancid, mould forms. The honest case for buying small and storing correctly.
Fish careLive foods for freshwater fish
Which live foods suit which fish, safest sources, and the parasite / water-quality watchouts.
Fish careHow to tell the sex of a fish: species-by-species guide
Gonopodium, breeding tubercles, vent sexing, and why some species are genuinely almost impossible. Every common species covered.
Fish careThe 101 guide to rams: German Blue Ram, Bolivian Ram, Electric Blue Ram
Why GBRs keep dying, what they actually need, how to breed them, and whether to choose a Bolivian Ram instead.
InvertebratesScuds in your aquarium: I got 99 problems but scud ain't one
What they are, how they got there, whether to panic, and why experienced keepers actually culture them on purpose.
Water qualityCan you use rainwater in a fish tank?
Yes — with caveats. pH 5.6, near-zero hardness, zero chlorine. Who benefits, who doesn't, and how to collect and treat it safely.
Getting startedBeginner coldwater fish tank setup: no heater, but no shortcuts
The right fish, the right equipment, and why goldfish are harder than they're sold as. A setup guide that actually tells you the truth.
Water qualityHow do I stop my fish tank water evaporating?
You can't stop it — but you can reduce it by 90% and understand what happens to your chemistry if you don't top up correctly.
Fish healthEpistylis — the complete guide (including how to tell it from ich)
Commonly misdiagnosed as ich, columnaris, or fungus. Here's exactly what Epistylis looks like, how to tell them apart, and what actually works.
InvertebratesWood shrimp — bamboo shrimp, Singapore shrimp, fan shrimp: complete guide
All the common names for one species, how filter feeding actually works, and whether they can ever breed in captivity (the honest answer).
Water qualityWhat do GH and KH mean — and why do they matter?
Two different types of “hardness” that mean completely different things. One affects your fish. The other controls whether your pH will hold or crash overnight.
Plants & algaeSiamese algae eaters & black beard algae
What true SAEs eat, BBA limits, other algae — and telling them from lookalikes.
Fish careBetta biting its own fins: causes & fixes
Self-inflicted tail damage — flow, stress, boredom — and how it differs from fin rot.
Water qualityFreshwater Master Test Kit explained
The hobby’s default liquid kit: what it includes, what it skips, strips vs liquids.
Plants & algaeFertilizer in fish tanks: what to know
Fish, shrimp, nitrate budget, copper traces — beyond NPK alone.
InvertebratesWhy are my snails dying?
Copper, pH crash, starvation, predation — diagnosing and fixing snail deaths.
StockingCan angelfish live with neon tetras?
The risks, the conditions that make it work, and the alternatives if it doesn’t.
Fish careNeon tetra guide: 10 things every fishkeeper needs to know
Care, water, schooling, disease, lifespan — everything about the hobby’s most iconic fish.
Myth bustingThe 1 inch per gallon rule is wrong
The most famous stocking rule in the hobby — and why it's responsible for more fish deaths than almost any other advice.
Myth busting7 goldfish myths that are keeping fish miserable
Bowls, 3-second memory, growing to fit — goldfish are the most mistreated fish in the hobby because of these myths.
Myth bustingCycling myths that kill fish every day
Clear water isn't safe water. 6 cycling myths debunked — including the ones that cause the most beginner deaths.
Myth bustingBetta fish myths debunked
The cup is not a home. Bettas need heat, space, and a cycled tank. 8 myths corrected with evidence.
Myth busting10 fishkeeping myths that need to die
Water changes stress fish. Salt helps everyone. Clear water is safe. All wrong — 10 myths corrected.
MaintenanceUpgrading your tank: how to migrate your fish over
Use the old filter or seed the new one — never start a bigger tank with an uncycled filter.
Fish careSo you bought a small betta tank and now want a bigger one
Super common. How to upgrade without a cycle crash or a stressed betta.
InvertebratesNerite snails: shell issues and what to look for
Erosion, pitting, cracks — causes (water, diet, calcium) and what you can do.
InvertebratesSnail health: what to look out for with snails
Shell, activity, feeding, water — key things that keep snails healthy.
Getting startedHow to set up a fish tank
Step-by-step: tank, filter, cycle, then fish. No shortcuts.
Water & cycleWhy is my fish gasping at the surface?
Common causes (ammonia, nitrite, oxygen) and what to do now.
Water & cycleFish staying at top of tank
Causes, data, and actions. Oxygen, ammonia, gill disease, or normal behaviour?
Getting startedHow long does it take to cycle a fish tank?
Usually 2–6 weeks. What affects it and when you can add fish.
Plants & algaeBest aquarium plants for beginners
Easy, low-light plants: java fern, anubias, hornwort, and more.
Plants & algaeHow to tell if an aquarium plant is healthy
Leaf colour, new growth, roots, pearling vs deficiencies—and when algae is masking the real story.
Illness & hospitalBetta fins damaged: why and what to do
Fin rot, nipping, sharp decor. When water params are OK, it's usually physical.
Fish careWhy is my betta (Siamese fighting fish) not eating?
Stress, water quality, temperature, or picky feeding — what to check.
Fish careWhy is my betta fish hiding?
Rational causes: water quality, stress, tank mates, illness. What to check and red flags.
Fish careCan neon tetras live with bettas?
Tank size, group size, and how to keep both happy.
Fish careAngelfish (angel fish) care guide
Tank size, water, feeding, and temperament basics for healthy angelfish.
StockingBest angelfish (angel fish) tank mates
Compatible fish, species to avoid, and calm community setup tips.
StockingAngelfish (angel fish) tank size guide
How much space angelfish need for single, pair, and community setups.
Fish careCompare guppy and platy
Hardiness, temperament, breeding, and which livebearer suits your tank.
Fish careTypes of cichlids
South American, African, and dwarf cichlid groups explained.
Getting startedFreshwater vs saltwater aquarium
Cost, complexity, maintenance, and which is better for beginners.
Getting startedFree aquarium apps: what free really means
How to compare truly free, freemium, and free-trial aquarium apps.
Fish careBest beginner aquarium fish
Easy starter species and practical stocking advice.
Fish careTropical fish keeping tips
Simple habits that keep tropical freshwater tanks stable.
MaintenanceComparing different aquarium filters
HOB, canister, sponge, and internal filter pros and cons.
Getting startedBest aquarium substrate
Sand vs gravel vs planted substrate for common tank goals.
Water & cycleArchimedes water displacement: measure your aquarium’s real water volume
Apply a 2,200-year-old principle to work out substrate, rocks, and decor displacement — and why it matters for dosing and stocking.
Water & cycleHow to lower nitrate in your aquarium
Water changes, plants, feeding, and maintenance that work.
Water & cycleHow to track aquarium water parameters
What to test (pH, ammonia, nitrite, nitrate), how often, and how to spot problems before they hurt your fish.
MaintenanceAquarium maintenance schedule for beginners
A simple weekly and monthly routine: water changes, testing, filter care, and staying consistent.
Getting startedFish tank cycling: how to cycle a fish tank
Step-by-step fish tank cycling: fishless vs fish-in, what to test, and when it's safe to add fish.
Getting startedFish dying in new tank
New tank syndrome, overstocking, acclimation. Data, causes, and how to fix it.
StockingBest fish for a 10 gallon tank
Stocking ideas: bettas, nano schooling fish, and what to avoid in a small tank.
Water & cycleHow often to change aquarium water
By tank size, stocking, and experience — so you don't underdo or overdo it.
Water & cycleFish dying after water change
Temperature shock, chlorine, pH swing. Data to collect, causes, and prevention.
Fish careBetta (Siamese fighting fish) care guide
Tank size, temperature, tank mates, and what to avoid.
Fish careBetta bubble nests: what they mean and what to do
Why male bettas build bubble nests, myths, and whether to remove them.
Fish careSiamese fighting fish vs betta: what's the difference?
Short answer: nothing. Same fish, different name.
Illness & hospitalIch (ick): what it is, what it looks like, and how to treat it
White spots, causes, and practical treatment steps.
Illness & hospitalColumnaris: what it is and what to do
Cotton wool disease, saddleback — bacterial infection: symptoms, antibiotic treatment, and prevention.
StockingCombining fish: why species matter (e.g. two male bettas)
Compatibility and aggression — and why you should never keep two male bettas together.
StockingFish origins & biotope: why matching regions helps
Why keeping fish from similar origins can mean easier maintenance and more natural behaviour.
InvertebratesMystery snails: why they appear and what to do
Hitchhikers vs intentional snails, and whether you need to do anything about them.
InvertebratesHydra in aquarium: what they are and how to remove them
Tiny cnidarians that hitchhike on plants. Risk to fry and shrimp, treatment, and prevention.
Plants & algaeAlgae 101: the good, the bad, and the ugly
Types of algae, when they're a problem, and practical treatments that work.
Plants & algaeBiofilm in aquariums
That slimy coating on wood or plants — what it is, when it's harmless, and when to act.
Plants & algaeBlack beard algae: ten ways to target it
BBA is stubborn. Light, nutrients, manual removal, spot treatment, and prevention.
Water & cycleThe nitrogen cycle in aquariums
How ammonia becomes nitrite and nitrate — and why that chain matters for every tank.
Illness & hospitalNeon tetra disease
Symptoms, which tetras it affects, and what to do when you see it.
Illness & hospitalMy child's fish died — what to do
Practical steps, how to talk about it, and why parents often end up doing the care.
Illness & hospitalEuthanizing fish: humane methods and what to avoid
Clove oil step-by-step, inhumane methods to avoid, and facts vs myths. Veterinary-backed guidance.
Getting startedFishless cycle: to do or not to do?
The trade-offs — patience vs convenience, fish welfare vs real-world constraints.
StockingOverstocking: why optimal bioload matters
Why stocking depends on filtration, species, and how experienced you are.
Getting startedWhat should I get as my first tank?
Why a bigger first tank can be easier to manage than a tiny one.
InvertebratesCleanup crew: the dream team
Efficient combinations of snails, shrimp, and fish for algae and detritus.
Fish careBreeding: how easy is it, and should you do it?
Livebearers vs egg-layers and whether breeding is right for you.
Fish careLivebearers vs egg-layers: implications for your aquarium
How breeding style affects population, bioload, and stocking. What to expect with males and females.
Fish careLivebearers: how fast they breed & how long they live
Gestation ranges, sperm storage surprises, and realistic captive lifespans for guppies, platies, mollies, and swordtails.
Plants & algaeOvercleaning: you're building an ecosystem
Why stepping back and letting your tank thrive can be better than constant intervention.
StockingNeon vs. cardinal tetras: for and against
Honest comparison — looks, hardiness, cost, and which fits your tank.
Fish careGoldfish: the fish, the myth, the legend
How big they get, how messy they are, and what they really need.
Fish carePond fish: types, building, filters and feeding
Goldfish, koi, shubunkin. How to build a pond, depth, filter options, feeding by season.
Illness & hospitalTop 10 fish illnesses you may see — and what to do
Ich, fin rot, velvet, dropsy, and more: symptoms and practical responses.
Illness & hospitalHospital tanks
Why you need one and how to set it up for sick or new fish.
InvertebratesAssassin snails: the James Bond of snails
License to kill — the hitman of the snail world. What they do and how to use them.
MaintenanceLighting: what are the different types?
LED, fluorescent, T5, and what to choose for fish-only vs planted tanks.
Water & cycleWhat to do when ammonia spikes
Test, water change, stop feeding, and fix the cause so your fish recover.
Water & cycleWhat to do when nitrite spikes
Water change, reduce feeding, and support the cycle until nitrite is zero.
Water & cycleWhy is my aquarium water cloudy?
Bacterial bloom, debris, or algae — how to tell and fix it.
Getting startedNew tank syndrome explained
Why fish die in new tanks and how to prevent it with cycling.
StockingHow many fish per gallon?
Inch-per-gallon is a rough guide; bioload and behaviour matter more.
StockingBest fish for a 20 gallon tank
Community fish, schooling species, and stocking ideas.
StockingWhat can you keep in a 5 gallon tank?
Betta, shrimp, or a very small nano setup — limits and options.
StockingBest betta (Siamese fighting fish) tank mates
Which fish and invertebrates can live with a betta? Tank size and species that work.
Fish carePlaty fish care guide
Tank size, water, feeding, and tank mates for these easy livebearers.
Fish careMolly fish care guide
Tank size, water parameters, feeding, and tank mates.
Fish careGuppy care guide
Tank size, water, feeding, and what to do when they breed.
Fish careHow to tell if a guppy is male or female
Anal fin, gravid spot, body shape — sexing guppies for breeding control.
Fish careAre guppies aggressive?
When guppies chase, nip, or stress each other — and how to fix it.
Fish careGourami care 101
Tank setup, water, feeding, and tank mates for dwarf, pearl, and honey gouramis.
Getting startedThe ethics of fishkeeping
How to be an ethically responsible aquarist: tank size, sourcing, and welfare.
StockingWild caught vs captive bred: what's the difference?
Hardiness, disease, sustainability, and cost — how to choose for your tank.
Illness & hospitalWhy are my fish dying when water parameters are OK?
Ammonia and nitrite are zero — hidden causes and what to check next.
MaintenanceHow to temperature match your new tank water
Avoid shock during water changes: match new water to your tank.
Fish careCorydoras care guide
Tank size, group size, substrate, feeding, and water parameters.
Fish careZebra danio care
Hardy schooling fish: tank size, group, and tank mates.
Fish careHarlequin rasbora care
Tank size, water, chili rasbora comparison, tank mates, and common illnesses.
Fish careOtocinclus care and tank setup
Small algae eaters: group size, feeding, and compatibility.
Illness & hospitalWhy did my fish die suddenly?
Common causes: water quality, stress, disease, and what to check.
Illness & hospitalFin rot: causes and treatment
What causes fin rot and how to treat it with water quality and medication.
Illness & hospitalSwim bladder disease in fish
Floating, sinking, or listing: causes and what to do.
Illness & hospitalHow to quarantine new fish
Why quarantine and a simple setup to protect your main tank.
Plants & algaeGreen water (algae bloom) fix
Free-floating algae: reduce light and nutrients, water changes.
Plants & algaeBrown algae in aquarium
Diatoms on glass and decor: common in new tanks and how to manage.
Plants & algaeAquarium plant fertilizer for beginners
When and how to fertilize; liquid vs root tabs.
Getting startedBest substrate for aquarium
Gravel, sand, and planted substrates: what to choose.
Getting startedAdding wood: water changing color?
Driftwood turning water brown? Tannins are harmless. What’s going on and what to do.
Plants & algaePotassium deficiency in aquatic plants
Yellow leaf edges, pinholes, weak growth — how to spot and fix it.
Getting startedTypes of aquarium and the impact of shape
Rectangle, cube, bow-front, hex, column — how shape affects fish, plants, and care.
Water & cycleSurface agitation: what it means and how it impacts you
Ripples, bubbles, and movement at the surface — oxygen, CO2, and your fish.
InvertebratesShrimps: the full aquatic list and differences
Cherry, amano, ghost, bamboo, vampire — care and differences between species.
InvertebratesShrimps: managing beauty and ease of care
Colour grades, difficulty, and how to choose shrimp that fit your experience.
InvertebratesBreeding shrimp: how-to guide
Tank setup, water params, feeding, and raising baby shrimp.
Water & cycleTannins and tanks: what does it actually mean?
Tea-coloured water, blackwater, humic acids — what tannins are and whether they matter.
Plants & algaeCO2 additive: what you need to know
Liquid CO2 vs injected CO2. What additives do and don’t do for plants.
Plants & algaeCO2 systems in fish tanks: what you need to know
Regulators, diffusers, when you need it, and how to run CO2 safely.
MaintenanceUsing an established filter when setting up a tank
Seed a new tank with cycled media — transfer methods, risks, and testing.
Fish careThe curse of dwarf gouramis: myth vs reality
DGIV virus, sourcing, quarantine, and safer alternatives like honey and pearl gouramis.
Fish careCelestial pearl danio / galaxy rasbora: discovery and care
2006 discovery in Myanmar, care basics, behaviour, and feeding.
Fish careOscars: keeping oscars and watchouts
Tank size, filtration, feeding, tank mates, HITH, and aggression.
StockingNeon duels: neon vs black neon and other combinations
Compare neon, black neon, cardinal, glowlight, rummynose, and ember tetras.
StockingCan angelfish live with neon tetras?
Compatibility, risks, when it can work, and safer alternatives.
Fish careFrozen fish food: defrost or straight in the tank?
Defrost vs frozen cubes. Best practice for feeding and water quality.
Fish careHow to raise fry: water quality, food and stress
Water quality, feeding, and reducing stress for baby fish survival.
Getting startedTypes of aquarium filters
HOB, canister, sponge: how they work and what to pick.
Getting startedFiltration 101: what to know about filters
Mechanical, biological, chemical. Why filters matter and how to choose.
Getting startedWhat is the Ferrari of filtration?
Premium filters: Fluval FX, Oase, Eheim Pro. When to invest.
MaintenanceMagnetic algae scrapers: are they worth it?
Pros, cons, when they work, and when to skip them.
Water & cycleWhat is Prime for fish tanks?
Seachem Prime: chlorine, chloramine, ammonia detox. How to use it.
MaintenanceAir stones: what to know
Types, when you need one, maintenance, and check valves.
MaintenanceHow to clean sand without stirring it up
Gravel vac technique, water level, avoiding cloudiness.
MaintenanceWhat size heater for aquarium?
Watts per gallon and placement for tropical tanks.
Fish careHow to acclimate new fish
Float and drip: reduce stress when adding fish to the tank.
Fish careDrip acclimation: how to drip acclimate fish
Step-by-step drip method for sensitive species. Tubing, drip rate, timing.
Fish careHow much to feed fish (and avoid overfeeding)
Simple feeding rules so ammonia and nitrate stay under control.
Fish careHow to prepare peas for fish
Why peas help with constipation and swim bladder. Step-by-step prep and safe feeding.
Water & cycleUsing tap water for aquarium
Dechlorinator, temperature, and when to test your tap.
Plants & algaeLive plants vs fake plants
Pros and cons for water quality, algae, and maintenance.
StockingPeaceful community tank fish
Species that get along: tetras, rasboras, livebearers, corydoras.
Fish careSigns of stress in fish
Clamped fins, hiding, gasping: what to check and fix.
Getting startedAquarium keeping in the USA
US gallons, tap water by region, retail, and regulations for American hobbyists.
Getting startedAquarium keeping in the UK
Litres and gallons, hard water, retail, and regulations for British hobbyists.
Getting startedAquarium keeping in Canada
US gallons and metric, regional water, cold winters, and regulations for Canadian hobbyists.
Getting startedAquarium keeping in Australia
Biosecurity, litres, tap water, hot climate, and regulations for Australian hobbyists.
MaintenanceCrystals in fish tanks: what's safe and what isn't
Quartz family: safe. Copper-bearing minerals: dangerous. Vinegar test and full safe vs avoid table.
Plants & algaeHow to get rid of hair algae
Manual removal, root cause fixes, and the Amano shrimp method that actually works.
StockingCentrepiece fish: how to choose the perfect showpiece
Popular, unusual, and rare centrepiece fish by tank size — with compatibility notes.
InvertebratesWhy are my snails dying?
Copper toxicity, pH crash, starvation, predation — 8 causes with diagnosis and fixes.
Getting startedHow much does it really cost to set up a fish tank?
Honest breakdown: budget, mid-range, and premium across UK, USA, EU, Canada, Australia, and NZ.
Fish careNeon tetra guide: 10 things every fishkeeper needs to know
Why they're not beginner fish, what kills them, NTD, and the full care card.
Myth bustedThe 1 inch per gallon rule is wrong
Why the most repeated stocking rule in fishkeeping is dangerously misleading — and what actually matters.
Myth busted7 goldfish myths that are keeping fish miserable
3-second memory. Bowls are fine. They stay small. All wrong — and all harmful.
Myth bustedAquarium cycling myths that kill fish every day
Clear water means safe. Cycling takes a week. Small tanks cycle faster. All wrong.
Myth bustedBetta fish myths debunked
The most misunderstood fish in the hobby — 6 myths and what bettas actually need.
Myth busted10 fishkeeping myths that need to die
Tapping on glass. Daily feeding. Natural balance. 10 myths and the evidence against them.
Browse by topic
Find guides by theme: water problems, stocking, fish health, getting started, or plants.
Aquarium water & cycle problems
- Ammonia spike
- Nitrite spike
- Cloudy water
- Crystal clear aquarium water
- Cloudy water and bacterial bloom
- New tank syndrome
- Green water (algae bloom)
- Brown algae
- Tap water for aquarium
- What is Prime for fish tanks
- Water parameters
- Freshwater Master Test Kit
- Water too acid or alkaline
- Water too hard
- Water change frequency
- Fish dying after water change
- Lower nitrate
- Fish gasping at surface
- Fish staying at top of tank
- Surface agitation
- Tannins and tanks
- Temperature match new water
- How to cycle a tank
- The nitrogen cycle
- Fishkeeping fundamentals for new aquarists
- Manage water quality with App-aquatic
- Can you use rainwater in a fish tank?
- Aquarium water evaporation
- GH and KH explained
Stocking & tank size
- How many fish per gallon
- 5 gallon tank
- 10 gallon tank
- 20 gallon tank
- 20 gallon community setups
- 30 gallon community setups
- 40 gallon community setups
- How to use a stocking calculator
- 50 litre tank setups
- 60 litre tank setups
- 100 litre tank setups
- 50 gallon tank setups
- 75 gallon tank setups
- 100 gallon tank setups
- 200 litre tank setups
- 300 litre tank setups
- Betta tank mates
- Angelfish tank mates
- Angelfish tank size
- Compare guppy and platy
- Livebearers: breeding speed & lifespan
- Community tank fish
- Combining fish
- Fish origins & biotope
- Wild caught vs captive bred
- Overstocking
- Neon vs cardinal tetra
- Neon duels: neon vs black neon
- Can angelfish live with neon tetras?
- Ram cichlids: GBR, Bolivian Ram, Electric Blue
- Harlequin rasbora care
- Celestial pearl danio / galaxy rasbora
- Dwarf gourami curse: myth vs reality
- Oscars: keeping and watchouts
- Loach types and roles
- Do fish grow to tank size? (myth)
- Stocking decisions with App-aquatic
Fish health & illness
- Why did my fish die suddenly?
- Fish dying when water params OK?
- Fish dying one by one
- Suddenly losing fish — what to do
- Internal and external parasites
- Fin rot
- Betta fins damaged
- Betta biting own fins
- Swim bladder disease
- Fish flashing
- Fish treats: safe options
- Peas for fish
- Quarantine new fish
- Signs of stress in fish
- How to raise fry
- Frozen fish food: defrost or not?
- Does fish food expire?
- Live foods for freshwater fish
- How to tell the sex of a fish
- Ich (white spot)
- Epistylis in fish
- Columnaris (cotton wool)
- Top 10 fish illnesses
- Neon tetra disease
- My child's fish died — what to do
- Euthanizing fish humanely
- Hospital tanks
- Betta not eating
- Betta hiding
- Betta bubble nests
- Can you keep female bettas together?
Getting started & setup
- How to set up a fish tank
- Pond fish: types, building, filters and feeding
- Ethics of fishkeeping
- How to cycle a tank
- Fish dying in new tank
- Fishless cycle: to do or not?
- How long does cycling take?
- First tank
- Substrate (gravel, sand)
- Best sand for aquarium
- Clean sand without stirring
- Filter types
- Filtration 101
- Ferrari of filtration
- Heater size
- Oxygen stones and bubblers
- Air stones
- Magnetic algae scrapers
- Acclimating new fish
- Drip acclimation
- When to add plants in cycle
- Changing from gravel to sand
- Moving house (with an aquarium)
- Aquarium care on holiday
- Upgrading your tank / migrating fish
- Using an established filter when setting up
- Stay on top of tank care with App-aquatic
- Small betta tank to bigger tank
- Angelfish care
- Freshwater vs saltwater aquarium
- Types of aquarium and shape impact
- Free aquarium apps
- Best aquarium substrate
- Comparing different aquarium filters
- Aquarium keeping: USA
- Aquarium keeping: UK
- Aquarium keeping: Canada
- Aquarium keeping: Australia
- Impact of fish tanks on ADHD
- Beginner coldwater fish tank setup
Plants & algae
- Beginner aquarium plants
- How to tell if plants are healthy
- Algae 101
- Biofilm
- Black beard algae
- Siamese algae eater
- Green water (algae bloom)
- Brown algae (diatoms)
- Plant fertilizer
- Fertilizer in fish tanks
- Potassium deficiency in plants
- CO2 additive
- CO2 systems in fish tanks
- Live vs fake plants
- Overcleaning (building an ecosystem)
Invertebrates (snails & more)
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