Cycle it, plant it, keep it clear

Keep a freshwater tank that actually thrives.

A calm, practical guide to keeping freshwater fish. We walk through setting up and cycling a tank, keeping the water right, choosing fish that get along, growing live plants, and heading off disease — written plainly, by people who have scrubbed an algae-covered glass at 11 p.m.

Aquarium Volume Calculator

Turn tank dimensions into US gallons and liters, plus the filled water weight your stand and floor must hold.

19.9 US gallons (75.5 liters)

Filled weight: about 166 lb (75 kg)

Glass, substrate, rock, and decor add weight beyond the water itself — budget extra capacity on your stand and floor for a fully aquascaped tank.

All free tools →

Fresh from the tank

50 guides
Aquarium Plants

Why Your Aquarium Plants Are Melting or Dying

New plants going mushy? Leaves yellowing for no reason? Here's how to tell melt from death, what's causing it, and when to wait it out.

July 4, 2026
Maintenance & Gear

A Simple Weekly Aquarium Maintenance Routine

A practical aquarium maintenance schedule that keeps water quality stable and fish healthy, with a checklist you can actually follow each week.

July 3, 2026
Health & Disease

How to Acclimate New Fish Safely

Learn why acclimation matters and how to do it right, with step-by-step guides for both float-and-release and drip acclimation, plus tips on quarantine.

July 3, 2026
Water Quality

How to Lower and Raise Aquarium pH Safely

Learn how to lower or raise aquarium pH safely using natural methods, why stable pH beats chasing a number, and how pH swings stress fish.

July 3, 2026
Maintenance & Gear

Going on Vacation: How to Feed Fish While Away

Heading out of town? Learn how to feed fish while on vacation safely, from short trips where you do nothing to week-long absences that call for an auto feede...

July 2, 2026
Tank Setup

Aquascaping Basics: Hardscape, Layout, and Focal Points

Learn how to use driftwood and rocks to build a balanced aquascape. Covers layout styles, the rule of thirds, focal points, and preparing hardscape safely.

July 1, 2026
Fish Profiles

Best Beginner Fish for a First Freshwater Aquarium

A practical roundup of hardy, easy-to-keep freshwater fish for new aquarists, with tank size notes, temperament tips, and a few species to avoid at first.

July 1, 2026
Health & Disease

Ich (White Spot): How to Identify and Treat It

Learn how to treat ich in freshwater aquariums: spot the symptoms early, understand the life cycle, and clear white spot disease safely.

July 1, 2026
Water Quality

New Tank Syndrome: Why Fish Die in a New Aquarium

New tank syndrome is an ammonia and nitrite spike in an uncycled tank. Learn why fish die, how to spot the symptoms, and what to do right now to save them.

June 30, 2026
Aquarium Plants

Best Low-Light Aquarium Plants for Beginners

Discover the best beginner aquarium plants that thrive in low light with no CO2 injection. Practical picks, care tips, and setup advice for new fishkeepers.

June 29, 2026
Maintenance & Gear

How to Feed Aquarium Fish Without Overfeeding

Learn how often to feed aquarium fish, how much food is enough, and the signs of overfeeding that quietly wreck water quality in freshwater tanks.

June 29, 2026
Health & Disease

Common Aquarium Fish Diseases and How to Spot Them Early

Learn to recognize the early warning signs of common freshwater fish diseases like ich, fin rot, velvet, and dropsy before they spread through your tank.

June 28, 2026
Fish Profiles

Goldfish Care: Why They Need More Room Than You Think

Goldfish can live 10 to 15 years, but only with the right setup. Here is what goldfish actually need in terms of tank size, filtration, and temperature.

June 28, 2026
Aquarium Plants

Carpeting Plants: How to Grow a Lush Foreground

Learn how to grow aquarium carpet plants like dwarf hairgrass, monte carlo, and baby tears. Covers CO2 needs, the dry start method, planting technique, and w...

June 27, 2026
Tank Setup

Aquarium Heaters: Sizing and Setting the Temperature

How to size an aquarium heater, choose the right temperature for tropical fish, and decide whether your tank actually needs one at all.

June 26, 2026
Fish Profiles

Betta Fish Care: Tank Size, Water, and Tankmates

Keep betta fish healthy with the right tank size, water parameters, temperature, and compatible tankmates. Practical guidance for new and seasoned keepers.

June 26, 2026
Health & Disease

Velvet Disease in Freshwater Fish: Symptoms and Treatment

Velvet (Oodinium) coats fish in fine rust-colored dust and spreads quickly. Learn how to confirm it with a flashlight, treat it safely, and stop it from comi...

June 26, 2026
Aquarium Plants

Java Fern, Anubias, and Other Plants That Won't Die

A practical guide to easy aquarium plants that thrive without CO2 or special substrate, covering java fern care, anubias care, and other low-maintenance opti...

June 25, 2026
Water Quality

Aquarium Water Parameters Explained for Beginners

Learn which aquarium water parameters matter, what the safe ranges are, and how to keep them stable for healthy freshwater fish.

June 24, 2026
Maintenance & Gear

Essential Aquarium Equipment for Beginners

A plain-language guide to every piece of gear a beginner needs before bringing fish home, from must-haves to useful extras.

June 24, 2026
Water Quality

How to Dechlorinate Tap Water for Your Aquarium

Tap water is almost always treated with chlorine or chloramine. Here's how to dechlorinate it safely before adding it to a freshwater fish tank.

June 24, 2026
Health & Disease

Dropsy in Fish: Symptoms and What You Can Do

Dropsy in fish causes a pinecone-like appearance as scales protrude outward. Learn what it is, why it happens, how to treat it, and whether it can spread to...

June 23, 2026
Fish Profiles

Cherry Shrimp Care in a Freshwater Tank

A practical guide to keeping Neocaridina shrimp: tank setup, water parameters, feeding, breeding, and choosing safe tankmates.

June 22, 2026
Tank Setup

How to Set Up Your First Freshwater Aquarium, Step by Step

Learn how to set up a freshwater aquarium the right way: from choosing a tank size and gear to cycling the water before your first fish.

June 22, 2026
Fish Profiles

Platy Fish Care: Hardy, Colorful, and Perfect for Beginners

Platys are forgiving freshwater fish that tolerate a wide range of water conditions and come in dozens of color forms. Here is how to keep them well.

June 21, 2026
Health & Disease

Swim Bladder Disorder in Aquarium Fish

Learn what causes swim bladder disorder, why fish swim sideways or float upside-down, and how to treat betta and other freshwater fish at home.

June 21, 2026
Fish Profiles

Mystery Snail Care: A Beginner's Cleanup Crew

Learn how to keep mystery snails healthy: right tank size, what they eat, how to protect their shells, and what to watch for as a beginner.

June 20, 2026
Aquarium Plants

How to Dose Fertilizers in a Planted Aquarium

Learn how to fertilize aquarium plants using root tabs, liquid fertilizers, and EI dosing. Covers macro and micro nutrients, schedules, and deficiency signs.

June 19, 2026
Tank Setup

How to Pick the Right Aquarium Filter

Compare HOB, canister, and sponge filters, learn how to size a filter for your tank, and choose the right flow rate for your fish.

June 19, 2026
Maintenance & Gear

Gravel Vacuuming: How to Clean Aquarium Substrate

Learn how to clean aquarium gravel with a siphon vacuum, get the technique right for sand substrate, and keep your tank healthier with less effort.

June 18, 2026
Tank Setup

Choosing Aquarium Substrate: Gravel, Sand, or Aquasoil

Compare gravel, sand, and aquasoil to pick the best aquarium substrate for your fish, plants, and budget. Practical depths, weights, and setup tips inside.

June 17, 2026
Water Quality

Understanding pH, GH, and KH in Freshwater Tanks

Learn what pH, GH, and KH mean for your freshwater aquarium, how they interact, and how to match them to your fish's needs.

June 17, 2026
Maintenance & Gear

How to Clean an Aquarium Filter Without Killing the Cycle

Learn how to clean your aquarium filter safely, rinse media in tank water, and avoid crashing your nitrogen cycle. Step-by-step guide for freshwater tanks.

June 16, 2026
Health & Disease

Why Your Fish Is Gasping at the Surface

Fish gasping at the surface usually signals low oxygen or poor water quality. Learn the top causes and how to fix them fast.

June 15, 2026
Aquarium Plants

Aquarium Lighting for Plants: How Much and How Long

Learn how much light planted tanks actually need, how long to run aquarium lights, and which PAR values suit low, medium, and high-tech setups.

June 14, 2026
Fish Profiles

Corydoras Catfish Care: The Friendly Bottom Dweller

Learn corydoras care basics: tank size, water params, diet, tankmates, and group size. A practical guide from a fellow hobbyist.

June 14, 2026
Water Quality

How to Do an Aquarium Water Change the Right Way

Step-by-step guide to aquarium water changes: how much to change, how often, and the right tools to keep your fish healthy.

June 13, 2026
Tank Setup

Fishless Cycling vs Fish-In Cycling: Which to Choose

Compare fishless cycling and fish-in cycling to pick the right method for your new aquarium. Includes timelines, ammonia tips, and what to watch for.

June 12, 2026
Maintenance & Gear

How to Get Rid of Algae in a Freshwater Tank

Practical steps to remove green water algae, black beard algae, and other common tank algae, plus how to stop it from coming back.

June 12, 2026
Health & Disease

How to Set Up and Use a Quarantine Tank

Learn how to set up an aquarium quarantine tank to protect your fish. Covers sizing, cycling, treatment protocols, and when to use a hospital tank.

June 11, 2026
Aquarium Plants

Do You Need CO2 for a Planted Tank?

CO2 injection isn't required for every planted tank. Learn when it helps, when to skip it, and how low-tech setups thrive without a pressurized system.

June 10, 2026
Fish Profiles

Neon Tetra Care and Ideal Tankmates

Learn neon tetra care essentials: tank size, water parameters, schooling needs, feeding, and the best tankmates for a thriving community aquarium.

June 10, 2026
Water Quality

Ammonia, Nitrite, and Nitrate: What the Numbers Mean

Learn what ammonia, nitrite, and nitrate levels mean for your freshwater aquarium, what's safe, and what to do when readings spike.

June 9, 2026
Tank Setup

The Nitrogen Cycle: How to Cycle a New Fish Tank

Learn how to cycle a fish tank the right way. Understand the nitrogen cycle, grow beneficial bacteria, and know exactly when your aquarium is safe for fish.

June 8, 2026
Health & Disease

Fin Rot: Causes, Treatment, and Prevention

Learn what causes fin rot in freshwater fish, how to treat it at home, and how to stop it coming back. Practical steps from diagnosis to recovery.

June 7, 2026
Maintenance & Gear

How to Clean Aquarium Glass and Remove Algae

Learn how to clean aquarium glass and remove green algae fast using the right scraper technique, safe products, and a routine that keeps glass clear long-term.

June 7, 2026
Aquarium Plants

How to Plant and Anchor Aquarium Plants

Learn how to plant aquarium plants correctly in gravel, sand, or on hardscape, with tips for anchoring rhizome plants and rooted stems.

June 6, 2026
Fish Profiles

Guppy Care Guide: Setup, Diet, and Breeding

Everything you need to keep guppies healthy: tank size, water parameters, feeding schedules, and how to breed them successfully at home.

June 5, 2026
Water Quality

How to Test Aquarium Water (and How Often)

Learn how to test aquarium water with liquid kits or test strips, what parameters to check, and how often to test for a healthy freshwater tank.

June 5, 2026
Tank Setup

What Size Aquarium Should a Beginner Get?

The sweet spot for a first fish tank is 20 gallons. Here's why bigger tanks are easier to manage and how to choose the right size for your space.

June 4, 2026

Browse by topic