9 Beginner Planted Aquarium Mistakes (Tips & Tricks)

By: Billy | September 21, 2022 | Planted Tanks

I made many beginner aquarium mistakes when building my first low-tech planted tank. I wish I had a simple resource I could reference when first starting. It would’ve made my aquarium journey more enjoyable.

So, I put this post together to make you aware of the things to avoid.

My first mistake was…

1. Minimal Research

beginner aquarium mistakes

I immediately went to my local pet store the day I got my aquarium. Like most beginners, I was overly excited about getting it set up. Long story short, I barely did any research. When I went to the store, I relied on one of the employees to pick the fish for me. They told me to get 5 Neon Tetra for my 5-gallon aquarium. This ended up being a bad idea.

Almost immediately after putting them in my tank, they started acting aggressively toward each other. I did some research and found out they’re a schooling fish. Meaning, they feel most comfortable in larger groups (colony). Usually, a minimum of 6 Neon Tetra are required for a colony.

2. Too Much Substrate

toomuch substrate

My original mindset was “the more, the better.” Specifically with the substrate.

I bought Fluval Stratum substrate for my 5-gallon aquarium and poured close to 3 inches of the substrate. I thought they needed a thick slab for the roots to hold. While that may be true for larger background plants, you don’t need that much for smaller foreground plants. A common technique is to use a small amount of substrate in the front and angle it upward towards the back.

Substrate is expensive, so don’t use a lot if you’re on a budget. Secondly, having more substrate means more nutrients, which increases your chances of algae outbreaks.

3. Direct Water Pour

direct water pour

When filling your tank with water, don’t directly pour your water in. When the water makes direct contact with the substrate, it’ll make a mess. You want something for the water to hit and evenly distribute.

Things you can use to break up your water pour…

Using something to break up your water will help control your water’s clarity. My mistake was that I laid my substrate, placed my plants, and immediately poured water. This was a bad idea because there was no barrier, so the water directly hit the substrate, creating extremely murky water.

Once you have some water in your tank, you can use a kitchen colander. They work wonders because there are so many holes, efficiently spreading out the water. I learned this trick from reading George Farmer’s Aquascaping book. I highly recommend reading it. That book helped me easily understand the basics of aquascaping.

4. Small Tank


My initial thoughts were that a smaller tank would be easier for a beginner. I ended up buying the Marineland 5-Gallon Portrait aquarium. While it’s easier to maintain plants in a smaller tank, it’s not easier to control toxic bacteria. A smaller tank is harder to regulate the water parameters because it’ll spread faster.

If I could do it over, I would’ve started with a 20-gallon aquarium. This would’ve allowed me to have more options of fish to stock.

5. Inconsistent Light

fluval nano light

I was so excited about having live plants in my aquarium that I didn’t put much thought into the lighting.

It wasn’t until most of my plants died that I began researching. The stock light with my Marineland 5-Gallon required me to manually turn it on and off. Some days I forgot to switch it on, which wasn’t good for the health of my plants.

I ended up buying this Fluval Nano light, which you can program to come automatically on and off. If you don’t want to spend that much for a light, you can plug your stock light into a cheap timer from Amazon.

However, keep in mind that it’s easy to overdo the lighting. The rule of thumb is to have your light on for 8 hours. Typically anything after 10 hours of lighting fuels algae growth.

There are some people out there (like MD Tanks) that keep their lights on for over 10 hours. But it’s usually a low-powered light. A lot of this advice is subjective, and you’ll need to test it for yourself.

6. Inconsistent Maintenance

maintenance tank

Since day one, my goal was to build a planted aquarium that required minimal maintenance.

But to be honest, every planted tank needs consistent maintenance. I don’t mean you have to do something every single day. But, you need to figure out a schedule that works for you and stick with it.

Keep an eye on it and address issues as they appear.

Doing water changes is one of the best things you can do to prevent any issues. Everyone has their own way of doing things, but I’ve found that a 30-50% water change once per week works well.

Again, this is subjective because I know people that don’t do water changes for several weeks. Figure out what works for your aquarium and lifestyle.

7. Overfeeding


I had a similar philosophy with feeding that I had with the substrate. “The more, the better,” I thought.

Again, this is wrong.

You want to create a balanced environment, and anything you overdo will likely cause an issue.

So, how much should you be feeding your fish? Well, it usually depends on the species. A general rule of thumb is to feed the size of your fish’s eyeball, daily.

If you overfeed them, that food will float to the bottom and cause unnecessary bacteria. And that bacteria will help fuel algae growth. If you have an issue with algae, check out this article which covers common solutions.

8. Filter Cartridges

aquarium filter cartridges

Most beginners will buy an all-in-one fish tank that uses filter cartridges. My first tank used these and I spent a good amount of money on buying new ones.

Then I found out this is a scam. You don’t need to continuously buy new cartridges! You can buy filter media and keep it in your tank.

Plus, it’s actually better for your ecosystem because you’re keeping the beneficial bacteria in your tank.

When you change out your filter every few weeks, you’re throwing away that beneficial bacteria.

9. Comparing Your Tank

comparing tank mistake

One of the biggest mistakes you can make is comparing your tank to the ones you find on Instagram.

You need to remember that those with decades of experience build those setups. On top of it all, they take many hours per week to maintain and will use Photoshop to clean up the images.

It can be discouraging to see how perfect those tanks are, but don’t let it get to you.

Enjoy the process of trial and error. It’s a journey. No one becomes a master overnight.

Bottom Line

Building your first tank doesn’t have to be complicated. Avoid these beginner aquarium mistakes, and you’ll be well on your way to a beautifully balanced planted tank.

Just remember, it’s all trial and error. What works for me might not work for you.

Don’t let that discourage you. Experimenting is part of the fun.


I've been building freshwater aquariums with my dad since a young age. A few years ago, I shifted my focus to low-tech planted tanks. My goal is to share my experience to help make yours easier.