Start Here
Start Here: Beginner’s Guide to Fish Keeping
By Rick Mileski Sr. | 50+ Years of Fish Keeping Experience
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Welcome to Beginners Fish Keepers!
Hi, I’m Rick — I’ve been keeping fish for over 50 years and I created Beginners Fish Keepers to help you avoid the mistakes I made when I first started out. Trust me, I’ve made plenty of them over the years!
If you’re new to the aquarium hobby, you’re in exactly the right place. This guide will walk you through everything you need to know to get started — from choosing the right tank to picking your first fish — in simple, plain English with no confusing jargon.
Follow these 6 steps and you’ll be way ahead of most new fish keepers!
Step 1: Choose Your Aquarium
For most beginners, a 20-gallon aquarium is the sweet spot. It’s large enough to provide a stable, healthy environment for your fish but small enough to manage easily as a beginner.
Here’s why tank size matters more than most people realize — smaller tanks like bowls or tiny 5-gallon tanks have very little water volume, which means water quality can go bad very quickly. A larger tank gives you more time to catch and correct any problems before they harm your fish.
My beginner recommendation:
- Aqueon 20 Gallon Aquarium Starter Kit — everything you need in one box
- Tetra 20 Gallon Complete Aquarium Kit — great budget friendly option
💡 Rick’s Tip: Always buy the largest tank your budget and space allows. In 50 years of fish keeping I’ve never heard anyone say their tank was too big — but I’ve heard plenty say it was too small!
Step 2: Cycle Your Aquarium
Before adding any fish, your aquarium needs time to build healthy beneficial bacteria. This process is called cycling the tank and it is honestly the most important step most beginners skip — and it’s the #1 reason new fish die.
These beneficial bacteria break down fish waste and keep toxic ammonia and nitrite levels from building up in your tank. A properly cycled tank can mean the difference between healthy, thriving fish and a tank full of dead ones.
Products you’ll need for cycling:
- API Freshwater Master Test Kit (read my full review) — essential for monitoring ammonia, nitrite, nitrate and pH during cycling
- Seachem Prime Water Conditioner — neutralizes chlorine and detoxifies ammonia during cycling
- [ Seachem Stability Biological Supplement — speeds up the cycling process significantly
💡 Rick’s Tip: Don’t rush the cycle. I know it’s tempting to add fish right away but patience here saves you from heartbreak later. A proper cycle takes 4-6 weeks but it’s absolutely worth the wait!
Step 3: Choose Beginner Friendly Fish
Not all fish are good choices for beginners. Some species are very sensitive to water quality changes and require more experience to keep successfully.
Hardy beginner friendly fish include:
- Platies
- Mollies
- Zebra Danios
- Corydoras Catfish
- Neon Tetras
- Guppies
- Bristlenose Plecos
Always research each fish before buying to make sure it fits your tank size and gets along with other fish you plan to keep.
Helpful products when adding new fish:
- API Stress Coat Water Conditioner — reduces stress when introducing new fish
- Seachem Prime — protects new fish during water changes
💡 Rick’s Tip: Visit your local fish store and ask questions before buying. A good fish store staff member will tell you honestly whether a fish is right for your setup. If they just try to sell you anything without asking about your tank — find another store!
Step 4: Essential Equipment
Every aquarium needs the right equipment to keep fish healthy. Here’s what you’ll need and my personal recommendations for each:
| Equipment | Why You Need It | My Pick |
|---|---|---|
| Filter | Keeps water clean and healthy | Aqueon Quietflow 20 Filter |
| Heater | Maintains tropical fish temperature | Eheim Jager Aquarium Heater |
| Thermometer | Monitors water temperature daily | API Liquid Thermometer |
| Water Conditioner | Makes tap water safe for fish | Seachem Prime |
| Fish Food | Quality nutrition for healthy fish | Fluval Bug Bites Tropical Fish Food |
| Water Test Kit | Monitors water quality parameters | API Freshwater Master Test Kit |
💡 Rick’s Tip: Don’t cheap out on your filter or heater. These two pieces of equipment are the life support system for your fish. Buy quality once rather than replacing cheap equipment twice!
Step 5: Add Fish Slowly
One of the most common mistakes beginners make is adding too many fish too quickly. Your aquarium’s biological filter needs time to adjust to each new addition.
Follow this simple rule:
- Start with 3-4 hardy fish maximum
- Wait 2-3 weeks before adding more
- Test your water before and after each addition
- Never add more than a few fish at a time
This gradual approach gives your aquarium’s beneficial bacteria time to grow and handle the increased waste load without causing dangerous ammonia spikes.
💡 Rick’s Tip: The most common phrase I hear from beginners is “I added too many fish too fast.” Take it slow — your fish will thank you for it!
Step 6: Regular Maintenance
Consistent maintenance is the secret to a healthy, beautiful aquarium long term. Don’t let this intimidate you — once you get into a routine it only takes 30-60 minutes per week.
Basic weekly maintenance:
- Perform a 20-25% water change with dechlorinated water
- Clean the glass when algae appears
- Test water parameters weekly
- Check equipment is running properly
- Remove any uneaten food
My recommended maintenance tools:
- Python No Spill Water Changer — makes water changes incredibly easy, no buckets needed!
- API Algae Scraper — keeps glass crystal clear
- Fluval Gravel Cleaner — removes waste from substrate during water changes
Regular water changes are honestly the single most important thing you can do for your fish after the initial setup. I’ve kept fish for over 50 years and I still do weekly water changes without fail!
💡 Rick’s Tip: Set a specific day each week for maintenance and stick to it. I do mine every Sunday morning with a cup of coffee — it becomes part of your routine and you actually start to enjoy it!
🐠 Join Our FREE Community!
Have questions? Want to show off your tank? Need advice from experienced fish keepers?
Join our FREE Beginners Fish Keepers Facebook Group — we have a friendly, helpful community ready to answer your questions and help you succeed!
👉 JOIN THE FACEBOOK GROUP HERE
We’re also on Skool with free beginner courses and step-by-step guides:
👉 JOIN OUR SKOOL COMMUNITY HERE
Continue Learning
Ready to dive deeper? Here are your next steps: