Pete's Aquatics checklist

Aquarium Cycling Cheat Sheet

A quick reference for knowing when a new aquarium is ready, what to test, and what to do when ammonia or nitrite shows up with livestock in the tank.

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Target Numbers

Parameter Goal Action point
Ammonia 0 ppm before adding livestock Any detectable ammonia with fish or shrimp needs immediate action.
Nitrite 0 ppm before adding livestock Any detectable nitrite with livestock needs immediate action.
Nitrate Present after the cycle develops Keep it controlled with water changes, plants, and routine maintenance.
Temperature Stable for your chosen livestock Avoid swings while the tank is cycling.
pH Stable Stability matters more than chasing one perfect number.

Fishless Cycle Checklist

  1. Set up the tank with filter, heater if needed, substrate, and dechlorinated water.
  2. Add an ammonia source.
  3. Test ammonia and nitrite every few days.
  4. Wait for ammonia to drop and nitrite to rise.
  5. Keep feeding the cycle until both ammonia and nitrite process back to 0 ppm.
  6. Confirm nitrate is present.
  7. Do a water change before adding livestock.
  8. Add fish or shrimp slowly.

Fish-In Emergency Checklist

  1. Test ammonia and nitrite immediately.
  2. Dose dechlorinator according to the label.
  3. Do a partial water change if ammonia or nitrite is detectable.
  4. Feed lightly until readings stabilize.
  5. Keep the filter running and do not replace all media.
  6. Retest daily until ammonia and nitrite are 0 ppm.

Common Mistakes

  • Replacing all filter media at once.
  • Rinsing filter media in untreated tap water.
  • Adding too many fish too quickly.
  • Trusting clear water instead of test results.
  • Chasing pH while ammonia or nitrite is the real problem.

A cycled tank is not a one-time achievement. It is a living filter. Protect it by keeping filter media wet, avoiding sudden livestock jumps, and testing whenever fish act stressed.

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