Fishkeeping guides for aquarists

Getting started

Fishkeeping fundamentals for new aquarists

A practical starter framework for setup, cycling, stocking, and maintenance.

Getting started

Using an established filter when setting up a tank

How to use a cycled filter to speed up a new setup. Transfer media safely.

Fish care

The curse of dwarf gouramis: myth vs reality

DGIV, hardiness, and how to improve your odds — or choose alternatives.

Fish care

Celestial pearl danios (galaxy rasboras)

Discovery story, care, and why these nano fish are worth the attention.

Fish care

Oscars: keeping them and what to watch out for

Tank size, feeding, HITH, and common pitfalls for these big cichlids.

Stocking

Neon duels: neon vs black neon and other tetras

Compare neon, black neon, cardinal, glowlight, rummynose — and how to mix.

Stocking

Can angelfish live with neon tetras?

Risks, when it might work, and safer alternatives.

Plants & algae

CO2 systems in fish tanks: what you need to know

When you need it, pressurized vs DIY, and fish safety.

Fish care

Loach guide: types and their role in the tank

Kuhli, clown, yo-yo, dwarf chain — what each does and how to keep them.

Water & cycle

How to manage water quality with App-aquatic

Track core readings, review trends, and respond quickly before fish are stressed.

Maintenance

How to stay on top of tank care with App-aquatic

Use reminders and logging to keep a reliable care rhythm.

Stocking

How to make the right stocking decisions with App-aquatic

Use compatibility and bioload checks before adding fish.

Maintenance

Oxygen stones and bubblers

What they do, when they help with oxygen, and whether you need one.

Illness & hospital

Suddenly losing fish — what to do

Step-by-step response when fish die, including when readings look fine.

Illness & hospital

Why are my fish dying one by one?

Sequential deaths: chronic stress, disease spread, aggression. Data, causes, and actions.

Illness & hospital

Internal and external parasites in fish

Types, symptoms, chemical and natural treatment. Ich, flukes, velvet, nematodes, hexamita.

Water & cycle

How to keep your fishtank water crystal clear

Filtration, water changes, feeding, and fixing cloudy or green water.

Fish care

Can you keep female bettas together?

Sorority tanks: when they work, tank size, and when to avoid.

Illness & hospital

Fish flashing: causes and what to do

Why fish rub on surfaces and how to diagnose before treating.

Getting started

When to add plants in your cycle

Best timing for plants in new tanks and how they support stability.

Maintenance

Changing from gravel to sand

A safe substrate swap plan that protects your cycle.

Maintenance

Best sand for your aquarium

How to choose the right type of sand for fishkeeping and your tank.

Water & cycle

Cloudy water and bacterial bloom

Why milky water happens and how to clear it safely.

Fish care

Fish treats: what can you safely give your fish?

Treat ideas, feeding frequency, and foods to avoid.

Stocking

Do fish grow to tank size? Fact or myth

Why stunting is not healthy adaptation and what to do instead.

Getting started

Impact of fish tanks on ADHD

A practical, non-medical look at routine, focus, and calm.

Invertebrates

Isopods: what they are, where they come from, should you worry

What they look like, where they come from, and whether to be worried.

Water & cycle

What 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 & cycle

What to do if your water is too hard

GH and KH explained, when it matters, and how to soften or work with your tap.

Stocking

Great setups for a 20 gallon community tank

Example combinations: tetra and cory, betta community, livebearers, and more.

Stocking

Great setups for a 30 gallon community tank

More room for schools and centrepieces. Example combinations that work.

Stocking

Great setups for a 40 gallon community tank

Larger schools and more variety. Example peaceful community setups.

Stocking

How to use a stocking calculator

Plan fish combinations, check compatibility, and avoid overstocking before you buy.

Stocking

Good setups for a 50 litre tank

Community, centrepiece, and nano options for ~13 gallon tanks.

Stocking

Good setups for a 60 litre tank

Community and centrepiece options for ~16 gallon tanks.

Stocking

Good setups for a 100 litre tank

Community, centrepiece, and dwarf cichlid options for ~26 gallon tanks.

Stocking

Good setups for a 50 gallon tank

Community, centrepiece, and cichlid options for ~190 litre tanks.

Stocking

Good setups for a 75 gallon tank

Community, centrepiece, and cichlid options for ~284 litre tanks.

Stocking

Good setups for a 100 gallon tank

Community, centrepiece, and cichlid options for ~380 litre tanks.

Stocking

Good setups for a 200 litre tank

Community, centrepiece, and cichlid options for ~53 gallon tanks.

Stocking

Good setups for a 300 litre tank

Community, centrepiece, and cichlid options for ~80 gallon tanks.

Maintenance

What to do when moving house (with an aquarium)

Plan the move: keep fish safe, save your cycle, and set up again without disaster.

Maintenance

Aquarium 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.

Maintenance

Upgrading 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 care

So 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.

Invertebrates

Nerite snails: shell issues and what to look for

Erosion, pitting, cracks — causes (water, diet, calcium) and what you can do.

Invertebrates

Snail health: what to look out for with snails

Shell, activity, feeding, water — key things that keep snails healthy.

Getting started

How to set up a fish tank

Step-by-step: tank, filter, cycle, then fish. No shortcuts.

Water & cycle

Why is my fish gasping at the surface?

Common causes (ammonia, nitrite, oxygen) and what to do now.

Water & cycle

Fish staying at top of tank

Causes, data, and actions. Oxygen, ammonia, gill disease, or normal behaviour?

Getting started

How long does it take to cycle a fish tank?

Usually 2–6 weeks. What affects it and when you can add fish.

Plants & algae

Best aquarium plants for beginners

Easy, low-light plants: java fern, anubias, hornwort, and more.

Illness & hospital

Betta fins damaged: why and what to do

Fin rot, nipping, sharp decor. When water params are OK, it's usually physical.

Fish care

Why is my betta (Siamese fighting fish) not eating?

Stress, water quality, temperature, or picky feeding — what to check.

Fish care

Why is my betta fish hiding?

Rational causes: water quality, stress, tank mates, illness. What to check and red flags.

Fish care

Can neon tetras live with bettas?

Tank size, group size, and how to keep both happy.

Fish care

Angelfish (angel fish) care guide

Tank size, water, feeding, and temperament basics for healthy angelfish.

Stocking

Best angelfish (angel fish) tank mates

Compatible fish, species to avoid, and calm community setup tips.

Stocking

Angelfish (angel fish) tank size guide

How much space angelfish need for single, pair, and community setups.

Fish care

Compare guppy and platy

Hardiness, temperament, breeding, and which livebearer suits your tank.

Fish care

Types of cichlids

South American, African, and dwarf cichlid groups explained.

Getting started

Freshwater vs saltwater aquarium

Cost, complexity, maintenance, and which is better for beginners.

Getting started

Free aquarium apps: what free really means

How to compare truly free, freemium, and free-trial aquarium apps.

Fish care

Best beginner aquarium fish

Easy starter species and practical stocking advice.

Fish care

Tropical fish keeping tips

Simple habits that keep tropical freshwater tanks stable.

Maintenance

Comparing different aquarium filters

HOB, canister, sponge, and internal filter pros and cons.

Getting started

Best aquarium substrate

Sand vs gravel vs planted substrate for common tank goals.

Water & cycle

Archimedes 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 & cycle

How to lower nitrate in your aquarium

Water changes, plants, feeding, and maintenance that work.

Water & cycle

How to track aquarium water parameters

What to test (pH, ammonia, nitrite, nitrate), how often, and how to spot problems before they hurt your fish.

Maintenance

Aquarium maintenance schedule for beginners

A simple weekly and monthly routine: water changes, testing, filter care, and staying consistent.

Getting started

Fish 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 started

Fish dying in new tank

New tank syndrome, overstocking, acclimation. Data, causes, and how to fix it.

Stocking

Best fish for a 10 gallon tank

Stocking ideas: bettas, nano schooling fish, and what to avoid in a small tank.

Water & cycle

How often to change aquarium water

By tank size, stocking, and experience — so you don't underdo or overdo it.

Water & cycle

Fish dying after water change

Temperature shock, chlorine, pH swing. Data to collect, causes, and prevention.

Fish care

Betta (Siamese fighting fish) care guide

Tank size, temperature, tank mates, and what to avoid.

Fish care

Betta bubble nests: what they mean and what to do

Why male bettas build bubble nests, myths, and whether to remove them.

Fish care

Siamese fighting fish vs betta: what's the difference?

Short answer: nothing. Same fish, different name.

Illness & hospital

Ich (ick): what it is, what it looks like, and how to treat it

White spots, causes, and practical treatment steps.

Illness & hospital

Columnaris: what it is and what to do

Cotton wool disease, saddleback — bacterial infection: symptoms, antibiotic treatment, and prevention.

Stocking

Combining fish: why species matter (e.g. two male bettas)

Compatibility and aggression — and why you should never keep two male bettas together.

Stocking

Fish origins & biotope: why matching regions helps

Why keeping fish from similar origins can mean easier maintenance and more natural behaviour.

Invertebrates

Mystery snails: why they appear and what to do

Hitchhikers vs intentional snails, and whether you need to do anything about them.

Invertebrates

Hydra 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 & algae

Algae 101: the good, the bad, and the ugly

Types of algae, when they're a problem, and practical treatments that work.

Plants & algae

Biofilm in aquariums

That slimy coating on wood or plants — what it is, when it's harmless, and when to act.

Plants & algae

Black beard algae: ten ways to target it

BBA is stubborn. Light, nutrients, manual removal, spot treatment, and prevention.

Water & cycle

The nitrogen cycle in aquariums

How ammonia becomes nitrite and nitrate — and why that chain matters for every tank.

Illness & hospital

Neon tetra disease

Symptoms, which tetras it affects, and what to do when you see it.

Illness & hospital

My child's fish died — what to do

Practical steps, how to talk about it, and why parents often end up doing the care.

Illness & hospital

Euthanizing fish: humane methods and what to avoid

Clove oil step-by-step, inhumane methods to avoid, and facts vs myths. Veterinary-backed guidance.

Getting started

Fishless cycle: to do or not to do?

The trade-offs — patience vs convenience, fish welfare vs real-world constraints.

Stocking

Overstocking: why optimal bioload matters

Why stocking depends on filtration, species, and how experienced you are.

Getting started

What should I get as my first tank?

Why a bigger first tank can be easier to manage than a tiny one.

Invertebrates

Cleanup crew: the dream team

Efficient combinations of snails, shrimp, and fish for algae and detritus.

Fish care

Breeding: how easy is it, and should you do it?

Livebearers vs egg-layers and whether breeding is right for you.

Fish care

Livebearers vs egg-layers: implications for your aquarium

How breeding style affects population, bioload, and stocking. What to expect with males and females.

Plants & algae

Overcleaning: you're building an ecosystem

Why stepping back and letting your tank thrive can be better than constant intervention.

Stocking

Neon vs. cardinal tetras: for and against

Honest comparison — looks, hardiness, cost, and which fits your tank.

Fish care

Goldfish: the fish, the myth, the legend

How big they get, how messy they are, and what they really need.

Fish care

Pond fish: types, building, filters and feeding

Goldfish, koi, shubunkin. How to build a pond, depth, filter options, feeding by season.

Illness & hospital

Top 10 fish illnesses you may see — and what to do

Ich, fin rot, velvet, dropsy, and more: symptoms and practical responses.

Illness & hospital

Hospital tanks

Why you need one and how to set it up for sick or new fish.

Invertebrates

Assassin snails: the James Bond of snails

License to kill — the hitman of the snail world. What they do and how to use them.

Maintenance

Lighting: what are the different types?

LED, fluorescent, T5, and what to choose for fish-only vs planted tanks.

Water & cycle

What to do when ammonia spikes

Test, water change, stop feeding, and fix the cause so your fish recover.

Water & cycle

What to do when nitrite spikes

Water change, reduce feeding, and support the cycle until nitrite is zero.

Water & cycle

Why is my aquarium water cloudy?

Bacterial bloom, debris, or algae — how to tell and fix it.

Getting started

New tank syndrome explained

Why fish die in new tanks and how to prevent it with cycling.

Stocking

How many fish per gallon?

Inch-per-gallon is a rough guide; bioload and behaviour matter more.

Stocking

Best fish for a 20 gallon tank

Community fish, schooling species, and stocking ideas.

Stocking

What can you keep in a 5 gallon tank?

Betta, shrimp, or a very small nano setup — limits and options.

Stocking

Best betta (Siamese fighting fish) tank mates

Which fish and invertebrates can live with a betta? Tank size and species that work.

Fish care

Platy fish care guide

Tank size, water, feeding, and tank mates for these easy livebearers.

Fish care

Molly fish care guide

Tank size, water parameters, feeding, and tank mates.

Fish care

Guppy care guide

Tank size, water, feeding, and what to do when they breed.

Fish care

How to tell if a guppy is male or female

Anal fin, gravid spot, body shape — sexing guppies for breeding control.

Fish care

Are guppies aggressive?

When guppies chase, nip, or stress each other — and how to fix it.

Fish care

Gourami care 101

Tank setup, water, feeding, and tank mates for dwarf, pearl, and honey gouramis.

Getting started

The ethics of fishkeeping

How to be an ethically responsible aquarist: tank size, sourcing, and welfare.

Stocking

Wild caught vs captive bred: what's the difference?

Hardiness, disease, sustainability, and cost — how to choose for your tank.

Illness & hospital

Why are my fish dying when water parameters are OK?

Ammonia and nitrite are zero — hidden causes and what to check next.

Maintenance

How to temperature match your new tank water

Avoid shock during water changes: match new water to your tank.

Fish care

Corydoras care guide

Tank size, group size, substrate, feeding, and water parameters.

Fish care

Zebra danio care

Hardy schooling fish: tank size, group, and tank mates.

Fish care

Harlequin rasbora care

Tank size, water, chili rasbora comparison, tank mates, and common illnesses.

Fish care

Otocinclus care and tank setup

Small algae eaters: group size, feeding, and compatibility.

Illness & hospital

Why did my fish die suddenly?

Common causes: water quality, stress, disease, and what to check.

Illness & hospital

Fin rot: causes and treatment

What causes fin rot and how to treat it with water quality and medication.

Illness & hospital

Swim bladder disease in fish

Floating, sinking, or listing: causes and what to do.

Illness & hospital

How to quarantine new fish

Why quarantine and a simple setup to protect your main tank.

Plants & algae

Green water (algae bloom) fix

Free-floating algae: reduce light and nutrients, water changes.

Plants & algae

Brown algae in aquarium

Diatoms on glass and decor: common in new tanks and how to manage.

Plants & algae

Aquarium plant fertilizer for beginners

When and how to fertilize; liquid vs root tabs.

Getting started

Best substrate for aquarium

Gravel, sand, and planted substrates: what to choose.

Getting started

Adding wood: water changing color?

Driftwood turning water brown? Tannins are harmless. What’s going on and what to do.

Plants & algae

Potassium deficiency in aquatic plants

Yellow leaf edges, pinholes, weak growth — how to spot and fix it.

Getting started

Types of aquarium and the impact of shape

Rectangle, cube, bow-front, hex, column — how shape affects fish, plants, and care.

Water & cycle

Surface agitation: what it means and how it impacts you

Ripples, bubbles, and movement at the surface — oxygen, CO2, and your fish.

Invertebrates

Shrimps: the full aquatic list and differences

Cherry, amano, ghost, bamboo, vampire — care and differences between species.

Invertebrates

Shrimps: managing beauty and ease of care

Colour grades, difficulty, and how to choose shrimp that fit your experience.

Invertebrates

Breeding shrimp: how-to guide

Tank setup, water params, feeding, and raising baby shrimp.

Water & cycle

Tannins and tanks: what does it actually mean?

Tea-coloured water, blackwater, humic acids — what tannins are and whether they matter.

Plants & algae

CO2 additive: what you need to know

Liquid CO2 vs injected CO2. What additives do and don’t do for plants.

Plants & algae

CO2 systems in fish tanks: what you need to know

Regulators, diffusers, when you need it, and how to run CO2 safely.

Maintenance

Using an established filter when setting up a tank

Seed a new tank with cycled media — transfer methods, risks, and testing.

Fish care

The curse of dwarf gouramis: myth vs reality

DGIV virus, sourcing, quarantine, and safer alternatives like honey and pearl gouramis.

Fish care

Celestial pearl danio / galaxy rasbora: discovery and care

2006 discovery in Myanmar, care basics, behaviour, and feeding.

Fish care

Oscars: keeping oscars and watchouts

Tank size, filtration, feeding, tank mates, HITH, and aggression.

Stocking

Neon duels: neon vs black neon and other combinations

Compare neon, black neon, cardinal, glowlight, rummynose, and ember tetras.

Stocking

Can angelfish live with neon tetras?

Compatibility, risks, when it can work, and safer alternatives.

Fish care

Loach guide: types and roles in the tank

Kuhli, clown, yo-yo, hillstream, zebra loaches and their roles.

Fish care

Frozen fish food: defrost or straight in the tank?

Defrost vs frozen cubes. Best practice for feeding and water quality.

Fish care

How to raise fry: water quality, food and stress

Water quality, feeding, and reducing stress for baby fish survival.

Getting started

Types of aquarium filters

HOB, canister, sponge: how they work and what to pick.

Getting started

Filtration 101: what to know about filters

Mechanical, biological, chemical. Why filters matter and how to choose.

Getting started

What is the Ferrari of filtration?

Premium filters: Fluval FX, Oase, Eheim Pro. When to invest.

Maintenance

Magnetic algae scrapers: are they worth it?

Pros, cons, when they work, and when to skip them.

Water & cycle

What is Prime for fish tanks?

Seachem Prime: chlorine, chloramine, ammonia detox. How to use it.

Maintenance

Air stones: what to know

Types, when you need one, maintenance, and check valves.

Maintenance

How to clean sand without stirring it up

Gravel vac technique, water level, avoiding cloudiness.

Maintenance

What size heater for aquarium?

Watts per gallon and placement for tropical tanks.

Fish care

How to acclimate new fish

Float and drip: reduce stress when adding fish to the tank.

Fish care

Drip acclimation: how to drip acclimate fish

Step-by-step drip method for sensitive species. Tubing, drip rate, timing.

Fish care

How much to feed fish (and avoid overfeeding)

Simple feeding rules so ammonia and nitrate stay under control.

Fish care

How to prepare peas for fish

Why peas help with constipation and swim bladder. Step-by-step prep and safe feeding.

Water & cycle

Using tap water for aquarium

Dechlorinator, temperature, and when to test your tap.

Plants & algae

Live plants vs fake plants

Pros and cons for water quality, algae, and maintenance.

Stocking

Peaceful community tank fish

Species that get along: tetras, rasboras, livebearers, corydoras.

Fish care

Signs of stress in fish

Clamped fins, hiding, gasping: what to check and fix.

Getting started

Aquarium keeping in the USA

US gallons, tap water by region, retail, and regulations for American hobbyists.

Getting started

Aquarium keeping in the UK

Litres and gallons, hard water, retail, and regulations for British hobbyists.

Getting started

Aquarium keeping in Canada

US gallons and metric, regional water, cold winters, and regulations for Canadian hobbyists.

Getting started

Aquarium keeping in Australia

Biosecurity, litres, tap water, hot climate, and regulations for Australian hobbyists.