Start where your tank is.
Water & Cycling
The nitrogen cycle, ammonia, nitrite, nitrate, water changes and dechlorinators.
Problems
Cloudy water, algae, disease and symptoms: cause, how to confirm it, fix, prevention.
Setup & Gear
Tanks, filters, heaters and the gear that actually matters for a freshwater tank.
Species
Care guides for small, popular freshwater fish, shrimp and snails.
Calculators
Fishless cycle dosing and water change planning, with the formulas on the page.
Recently reviewed
How Long Can Fish Go Without Food? What to Do Before a Trip
How long can fish go without food? A weekend is safe, a week is common, two is a gamble. See what each source says and how to prep your tank for a trip.
What Temperature Should a Fish Tank Be? A Chart by Species
What temperature should a fish tank be? A sourced chart for goldfish, bettas, guppies, tetras and shrimp, the range your fish share, and when to worry.
Hair Algae in a Fish Tank: Why It Comes Back and How to Clear It
Hair algae in a freshwater tank: pull it out, then fix light, feeding and heat so it stops growing back. Plus how many Amano shrimp it really takes.
Algae in a Fish Tank: Identify It by Color, Then Fix the Cause
Fish tank algae, identified by color: green, brown, black or blue-green. Which types are harmless, which mean trouble, and what to fix first in your tank.
How Much Aquarium Salt per Gallon? Doses, a Chart and When to Skip It
How much aquarium salt per gallon? Gram chart for 5 to 75 gallon tanks, why doses differ 5x, and which fish and plants may not take salt.
Ich Fish Treatment: How to Clear White Spot Disease From Your Tank
Ich fish treatment: how to spot white spot disease, why timing matters more than the dose, and what the sources say about salt, formalin and malachite green.
Every number has a source.
Temperatures, ammonia limits and dosing figures link to the agency, extension service or paper they come from. When a number is our own calculation or our inference, we say so.