Beginner guides

The basics every first-time fishkeeper needs, in plain English.

• How to Cycle a Fish Tank: Nitrogen Cycle Guide

  Cycle a new fish tank safely: what ammonia, nitrite and nitrate mean, fishless steps, steps if fish are already in, and how to know it has finished.

  7 minute read

• Aquarium Water Parameters: pH, GH and KH

  What pH, GH, KH, ammonia, nitrite and nitrate mean, how to test your tap water, how to read the results, and how to match your water to fish.

  6 minute read

• What Size Fish Tank Is Best for a Beginner?

  Why a bigger first tank is often easier, how a 20-gallon long compares with a 5-gallon, what a full tank weighs, and how size limits your fish.

  5 minute read

• How to Acclimate New Fish and Quarantine Them

  Bring new fish home safely: floating and drip acclimation, net or pour, a simple quarantine tank, and what to do if a new fish looks ill.

  7 minute read

• Aquarium Filter and Heater Guide for Beginners

  Sponge, hang-on-back and canister filters compared, gentle flow for long fins, how to size a heater, and the safety rules for water and electricity.

  6 minute read

• Why Is My Fish Tank Cloudy? Causes and Fixes

  Find out why your fish tank is cloudy with a simple white cup test: bacterial bloom, dust, waste or green water, and which ones to leave alone.

  4 minute read

• Why Is My Fish Tank Green? Causes and Fixes

  Green aquarium water is free-floating algae fed by light and nutrients. Learn why water changes alone fail, and how a UV sterilizer or a blackout clears it.

  4 minute read

• Why Are My Fish Dying? What to Check First

  If your fish are dying, start here: test the water, check the tank's age, and learn why water changes can help in a new tank but harm in an old one.

  4 minute read

• Why Is My Betta Fish Not Eating?

  A betta that stops eating usually has a water, temperature or food problem. Check these causes in order, and learn when to contact a fish expert.

  4 minute read

• How to Set Up a Freshwater Aquarium

  Set up a freshwater aquarium in the right order: position, gravel, water, equipment and cycling, plus what to do before any fish go in.

  3 minute read

• How Often Should You Change Aquarium Water?

  How often to change aquarium water and how much, why sources differ, how to do it safely, and the one case where a water change can harm your fish.

  3 minute read

• Ich in Fish: White Spots and What to Do

  Ich, or white spot disease, is a contagious parasite that can kill a tank quickly. Learn the signs, why treatment must be repeated, and how to prevent it.

  3 minute read

• How Many Neon Tetras in a 10-Gallon Tank?

  How many neon tetras fit a 10-gallon tank? Our main source asks for a larger tank and a group of at least 8. Here is why rules differ, and what to do.

  2 minute read

• How Often Should You Feed Aquarium Fish, and How Much?

  How often to feed aquarium fish and how much, why sources disagree, how to spot overfeeding, and how to feed bottom dwellers, night feeders and young fish.

  4 minute read