Fish Tank Crash Course
This site is completely free, open source, and built by a community of passionate fish keepers. Our goal is to help anyone at any age set up a thriving home aquarium while keeping the costs and on-going effort as low as possible.
- Start with hardy, peaceful species like guppies, platies, or white cloud minnows.
- Research adult size and schooling behavior.
- Avoid mixing aggressive and timid species in the same tank.
- 20-gallon tanks are ideal for beginners—stable and flexible.
- Glass is more scratch-resistant; acrylic is lighter and clearer.
- Ensure the stand or shelf can support full weight when filled.
- Use a sponge or hang-on-back filter for easy maintenance.
- Heater is essential unless you keep coldwater fish like goldfish.
- Consider a timer for your light to maintain consistency.
- Gravel is easy to clean and available in various colors.
- Sand is ideal for bottom-dwellers like corydoras.
- Plant-specific substrates improve root growth.
- Provide caves, wood, and structures for fish to hide and feel secure.
- Avoid sharp or jagged edges to prevent injuries.
- Balance decor with open swimming space.
- Start with low-light plants like java fern, anubias, or hornwort.
- Use root tabs for root feeders and liquid ferts for stem plants.
- Plants help stabilize the nitrogen cycle and reduce algae.
- Add substrate, decor, and fill slowly to avoid disturbing setup.
- Use dechlorinator before adding water or during filling.
- Install heater and filter according to instructions.
- Fishless cycling is safest—add bottled ammonia or fish food.
- Use beneficial bacteria (e.g., Fritz Zyme or Seachem Stability).
- Monitor ammonia → nitrite → nitrate over 4–6 weeks.
- Use liquid test kits (API Master Test Kit is a staple).
- Ideal: 0 ammonia, 0 nitrite, low nitrate (<40 ppm).
- Record values during and after cycling weekly.
- Float bag for 15–30 minutes to match temperature.
- Use the drip method or slow water addition for sensitive species.
- Turn off aquarium light during acclimation to reduce stress.
- Change 20–30% of water weekly using a siphon.
- Clean filter media in old tank water—not tap water.
- Feed sparingly to avoid excess waste buildup.
- Cloudy water: normal during cycling; avoid overfeeding.
- Algae: reduce lighting time or intensity; add live plants.
- Fish gasping at surface: check for ammonia or low oxygen.