Free tools for happier fish.

Quick calculators and plain-English guides for setting up and caring for a home aquarium, from a fishkeeper with over 10 years of experience and 18 tanks. About me.

Calculators

• Aquarium volume calculator
  Gallons, liters, weight, heater size and filter flow for any tank.
• Fish stocking calculator
  How many fish can my tank hold? Checks group sizes, temperatures and tankmates too.
• Water change calculator
  How much water to change today, and every week, to keep nitrate down.

Beginner guides

• Everything you need to start a fish tank
  The beginner checklist: must-haves, nice-to-haves and what to skip.
• How to cycle a new fish tank
  Grow the good bacteria before adding fish, step by step.
• Best fish for beginners
  10 hardy, peaceful fish, and the popular ones to avoid.
• Betta fish tank setup
  What a betta really needs to thrive, from tank size to tankmates.
• Cloudy aquarium water
  White, green or brown? What causes it and how to clear it.