Founder & Editor
Shon started keeping freshwater tanks the way most people do — badly, with a bowl and a goldfish that did not last. Aquarium for Beginners is the guide he wishes had existed then: specific numbers to test against, honest costs, and no advice that quietly assumes you already know what a nitrite spike is.
The best aquarium heater is right-sized, cuts out when dry and runs on a controller. See how heaters fail and which to buy for 5 to 75 gallon tanks.
The best food for betta fish is a betta pellet sized to its mouth. Six picks compared on label protein and pellet size, plus how many to feed a day.
The best substrate for planted aquarium setups depends on which plants feed by the root. Picks for 10 and 20 gallon tanks, with bag counts and costs.
The best tropical fish food for a community tank: a staple for the smallest mouths, a sinking food for bottom feeders, and a jar you can finish in 3 months.
Ghost shrimp breeding works in freshwater for most US ghost shrimp. How to spot the eggs, when they hatch, raising the larvae, and which kind needs salt.
How many guppies in a 10 gallon tank? Five, all male. Add females and two can drop 40 to 80 fry a month. See the breeding math and what to do instead.
How many neon tetras in a 10 gallon tank? Eight, kept on their own. Six is the floor and ten the ceiling. The math, plus how to add them without losses.
How to get rid of duckweed in an aquarium without hurting fish: net it, wipe the glass, pick it out of moss, then check for six weeks so it stays gone.
How to soften aquarium water: mix RO or distilled with tap at a measured ratio to lower GH. Get the formula, and why softeners and almond leaves fail.
How to tell if a mystery snail is dead: check its grip, its trapdoor, then the smell. Floating is not a sign. Then head off the ammonia spike.
A 10 gallon fish tank setup, item by item: about $185 in parts on a budget or $260 done properly, how much gravel it takes, and how to set it up.
The best filter for a 10 gallon tank depends on what lives in it. Picks for community, betta, shrimp and budget tanks, compared on maker specs.
The best filter for a 20 gallon tank, long or high: picks for community, goldfish, betta and budget tanks, compared on maker specs and flow.
Betta fin rot usually starts with dirty or cold water. How to tell it from tail biting, the clean-water fix, when to medicate, and how fins grow back.
To lower nitrates in a fish tank, change 50% of the water, then size your weekly change to fit. The tap water trap, the maths and which removers work.
To lower nitrites in a fish tank, change 50% of the water today and add a little aquarium salt to block it. Then fix the cause. Exact doses, sourced.
What fish can live with goldfish? Another goldfish first, then a few cool-water fish and snails, with temperatures, sizes and the ones to avoid.
Bettas rest on the bottom more than most fish, and often it means nothing. How to tell a resting betta from a cold or sick one, and what to check first.
Biofilm is the thin layer of bacteria on every surface in a tank, and most of it is useful. When surface film or slime is a problem, and how to fix it.
Black algae in a fish tank is almost always black beard algae: dark tufts on leaf edges and wood that will not wipe off. Why it grows and how to get rid of it.
Blue-green algae is cyanobacteria: a slimy sheet that peels off and smells like a swamp. Why it grows, how to remove it, and how to keep it from coming back.
Can a betta live with a goldfish? No. Goldfish need 20 gallons and strong filtration, bettas need calm water, and their temperatures barely overlap.
Dropsy in a betta shows as a swollen body with scales raised like a pine cone. What causes it, whether it spreads, early treatment, and when it is too late.
How big do goldfish get? Fancy goldfish reach 6–8 inches, commons 8–12 or more. Size by type and age, wild records, and what really stunts growth.
A healthy adult betta can go about a week without food, and survives up to two. How to plan a trip, which feeders to avoid, and why a betta stops eating.
A healthy adult goldfish can go a week without food easily and survives about two. How to prepare for a trip, why feeder blocks backfire, and ponds in winter.
How often to feed goldfish: once or twice a day, what they eat in 1-2 minutes. See how much in grams and a pond feeding chart by water temperature.
A betta floating sideways, stuck at the top or unable to leave the bottom usually has a digestion problem, not a disease. How to tell, and the 3-day fix.
White fuzz, film or crust in a fish tank is rarely algae. Most often it is harmless growth on new driftwood or mineral deposits. How to tell which one you have.
When fish keep dying one after another, the timing names the cause: a new tank, a water change, new fish or a neglected tank. How to find yours and stop it.
Black patches on a goldfish are often healing ammonia burns, which means the water was bad recently. Otherwise it is a natural colour change. How to tell which.
A goldfish fading to white is usually age, genetics or too little light. White spots, patches or fuzz are different. How to tell a harmless fade from a problem.
Brown algae in fish tank? It is almost always diatoms. How to confirm it, how long a new-tank bloom lasts, and what actually clears it.
A fish lying on the bottom of the tank is usually reacting to the water: ammonia, nitrite, temperature or oxygen. What to check first and what to do today.
How to get rid of snails in an aquarium: feed less, trap them overnight, and add assassin snails if you keep no snails you want. Skip the chemicals.
Hydra in an aquarium look like tiny stalks with tentacles. They are harmless to adult fish but eat fry and baby shrimp. How to starve them out or treat them.
Planaria in an aquarium are flatworms that glide on the glass. With fish they are harmless. In a shrimp tank, here is how to trap them and treat safely.
Worms in a fish tank are usually harmless detritus worms. Identify yours in one table, and learn the two that need action: planaria and camallanus.
What a 20 gallon fish tank setup costs in 2026, item by item: about $230 on a tight budget, $400–$500 done properly with a stand, and $10 a month to run.
Can you use distilled water in a fish tank? Not by itself — it has no minerals and cannot hold a stable pH. Use it for top-offs and to soften hard tap water.
How to change fish tank water: replace 25% once a week, with new water dechlorinated and matched to within 2°F. The steps, and how to set your own schedule.
Scuds in an aquarium are tiny curled crustaceans that swim on their side. With fish they are free live food. With only shrimp they are a rival.
Snail eggs in a fish tank look different for every species. Identify yours in one table — clear jelly, pink clutch or hard white dots — and if they will hatch.
Why does my fish tank smell? A healthy tank smells like damp soil. Rotten eggs, rotting fish and musty swamp each point to one cause — matched in one table.
Detritus worms in a fish tank are harmless waste eaters. A sudden bloom means overfeeding — and here is how to tell them apart from planaria, which are not.
How many fish in a 10 gallon tank? Six to eight small schooling fish, or one betta plus a clean-up crew — and why inch-per-gallon keeps killing tanks.
How much does a fish tank weigh? A filled 55 gallon comes to around 625 lb. Full weight table by tank size, plus what your floor can actually take.
How to acclimate fish to a new tank: float the bag 15 minutes, add tank water every 5 minutes for 20, then net them in. Never pour the bag water in.
How to clean aquarium decorations: hot water and a toothbrush for most of it, a 1:9 bleach soak for stubborn algae, then rinse and dechlorinate. Never soap.
Pothos in an aquarium is safe for fish and a strong nitrate exporter — roots in the water, leaves in the air. The real risk is the pesticide on the plant.
What temperature should a fish tank be? 76-78°F suits most tropical community tanks. Bettas want it warmer, goldfish cooler. Species chart inside.
Ammonia, nitrite and nitrate in plain English — how to run a fishless cycle step by step, and the one test that tells you the tank is ready for fish.
Small tanks are sold as beginner tanks but are the hardest to keep stable. How 5, 10, 20 and 29-gallon tanks compare on stocking, cost and forgiveness.
Want to know more about Aquarium for Beginners's editorial process? Read our about page.