Photo by Linus Nylund on Unsplash

Planted Tank vs. Fish Tank: Definition and Differences

To the untrained eye, there aren’t many differences between a planted tank and an aquarium full of fish and plants. Both have lighting, filtration, usually a heater, some hardscape in the form of rocks, driftwood, decoration, and probably substrate.

Indeed, the overlaps are plenty, but the truth is that a tank optimized for plants has subtle but impactful differences.

Here is a direct fish tank vs. planted tank comparison:

  • Lighting — Plants are much more sensitive to light than fish. Getting the right light for plants is essential for their growth and development.
  • Substrate — Fish can survive without substrate. Most plants need anchoring. Enriched substrates are created specifically for plants to thrive.
  • Filtration — Plants would be better off with filtration that doesn’t create strong currents, whereas some fish species prefer strong water flow.
  • Aeration — Both plants and fish need oxygen, but plants benefit massively from CO2, which is their main energy source.
  • Maintenance — A tank without plants is easier to maintain. Respectively, plants need trimming and replanting, possibly fertilization, among other things.

These are the main differences between planted tanks and fish tanks. There are other smaller nuances that tie into this.

Let’s explore them all in detail.

Water Parameters for Aquarium Plants

Before we go any further, a foreword about the technical requirements for owning aquarium plants.

Just like any living creature in your tank, plants need certain water parameters to thrive. The usual suspects of pH, KH, GH, and TDS affect plants in one way or another. But while the signs of stress in fish are relatively easy to recognize, diagnose, and (hopefully) cure, with plants things are way subtler.

An obvious sign of decay can be caused by several deficiencies or water imbalances and that complicates things considerably.

The main way plants “eat” is through CO2 and light, for this is the fuel of photosynthesis. But plants need macronutrients like potassium, calcium, magnesium, phosphorous, and even sulfur.

How do you measure those things?

Well, at least with certain ammonia tests you can measure nitrogen. Plants love themselves some nitro-gas.

Feeding fish is easy. Feeding plants, especially without fertilizer, is a lot of guesswork early on. That’s why planning a planted aquarium requires research, followed by closed observation and careful experimentation.

Read the article to the end to understand how each of the setup elements and maintenance sessions interact with one another, then check out pretty plants online. See what water conditions those you like require and plant a few. Not too many species, maybe two or three to begin with.

Plant, observe, and continue experimenting by adding new species every now and again.

Not all plants will survive, but as your knowledge grows you will learn what certain species lack and how to provide it for them.

But let’s start with the basics.


Lighting is one of the most crucial elements when setting up an aquarium. It often is the second-most expensive item after the filter (or the most expensive) and massively impacts the looks of the tank.

Fish don’t necessarily need light that much — they can live in darkness for quite a while, really — but we do, to see them and appreciate them. And plants need light to survive. Not necessarily abundance or high-intensity light, but the right amount, at the right strength.

But what does that mean? How strong a light do plants need and for how long?

Lighting is one of the most complicated topics in the aquarium hobby. Too much light and you end up with algae. Too few, and plants can start dying. And you still might get algae, but for different reasons.

Lights designed for planted tanks aren’t the cheapest lighting options available at your local fish store. Some models are outright expensive, and others are moderately priced, but still cost a bit. What you purchase shouldn’t depend only on budget, though. It must be based also on the type of plants you want to grow, as each species comes with its set of requirements.

The options are plentiful.

The ways to kill your plants also.


The substrate is another massive factor in planted tanks. The options are numerous, but the main division is between active and insert substrates.

Active substrates are enriched with nutrients, naturally or artificially. They are designed to support plant life, but before you run to the fish store for a few bags, better read the next paragraph, too.

Enriched substrates are great when you know what you are doing. Their potency requires careful handling or you’ll end up with algae problems and ammonia buildup. Algaes make things messy and can kill plants by covering their leaves and suffocating them. Ammonia is toxic for all livestock.

Inert substrates — gravel, sand, or pebbles — don’t have any nutrients, but plants can grow happily in them. Fish waste and uneaten food, as well as rotting leaves, dissolve into plant food. Adding fish to a planted tank will effectively supply nutrients to the water column and, over time, to the substrate.

See, all water plants feed through their leaves. Some species are considered root feeders, i.e. acquire a lot of nutrients through their roots, but all aquarium plants feed through their leaves as well. Here’s a more detailed breakdown on root feeders and a list of popular aquarium species.

However, a substrate for planted tanks should be evaluated not only on its aesthetic value, which usually is the main concern when keeping only fish.

You should consider the following:

  • Does it anchor the plants well enough? Fine sand poses certain difficulties in that regard.
  • Is it easy to plant into it? Pebbles are pretty but not the easiest to plant into.
  • Does it need additional fertilization? Root tabs or liquid fertilizers, even with livestock, can help in plant development.
  • Will you get aqua soil? Do you have the budget for it and, more importantly, the knowledge to handle it?


Filtration for fish tanks can be generalized rather easily — the more powerful, the better. Granted, there are many nuances to it, as well, but a powerful filter keeps the water column safe for the fish.

When it comes to plants, things become a bit more complicated. One thing that almost no plant appreciates is a strong current. Placing them directly in front of the power filter will likely kill them.

Now, plants like currents, as the moving water brings along nutrients. That’s why placing your aquatic shrubbery in dead spots, with weak or no water circulation, can also damage the plants. Either alga will start appearing or the plants won’t reach enough nutrients and aeration.


Plants need carbon dioxide (CO2) and oxygen (O2) to grow. They breathe the latter and feed on the former while photosynthesizing. Plants are awesome because they produce O2, helping all living critters breathe. They do so by absorbing the carbon (C) from CO2. On a molecular level, plants are mostly carbon, so it is essential for their diet.

But at night plants, water or terrestrial, don’t photosynthesize. They rest. While resting, they still need oxygen because all living things breathe 24/7.

Supplying the plants in your tank with enough O2 and CO2 is crucial for survival. That can be done with various filters in a low-tech setup. Dedicated planted tanks usually use a CO2 supply in the form of CO2 injections or through a carbon dioxide system that delivers it to the water column.

There are low-tech methods to create different chemical processes in your tank and trigger other growth pathways for your plants’ DNA. A very thick substrate will form layers of various chemical and biochemical compositions. Biowaste and mulm will slowly make it through the substrate, infusing it, and being infused by it.

The aquarium probably won’t look like the most stunningly curated aquascape out there, but plants love thick, layered substrate.


Live plants require maintenance. That’s true for house plants, gardens, greenhouses, crop fields, orchards, and aquarium plants.

Water plants need trimming, replanting, and cleaning. They will benefit from adequate fertilization, too.

Siphoning the bottom of the tank also becomes slightly more cumbersome, as you don’t want to damage or uproot the plants.

What Does “Beginners Plants” Mean?

You will often hear or read about “beginner plants”. The term definitely doesn’t mean “plants you can’t kill”. 

Beginner plants usually include species:

  • Durability  — They have their own source of food (Tiger lotus) or are voracious eaters (Vallisneria)
  • Adaptability — Can grow in a relatively wide variety of substrates

I’d add prolificity, as a good starting plant should be able to cover substantial parts of your fish tank quickly. All the same, you’ll often see Anubias on such a list because it exhibits the first two beginner virtues on the list.

Beginner plants is an umbrella term, but all the plants you’ll see it cover need a certain level of expert maintenance and the right conditions. Most budding fishkeepers tend to find success in growing species like cryptocorynes and Saggitaria, but all of us have seen them wilt and die at one point or another, too.

When choosing plants, do your due diligence and understand what they need to survive. Don’t choose the cheapest light. Be brave in experimenting but only once you understand what makes them grow in the first place.

Do You Need Fish in Your Planted Tank?

After seeing all the impactful differences between planted and fish tanks, the question becomes: 

Do you want to spoil your aquatic garden with fish?

Fish that poop, move around, chew or uproot plants, and break trunks.

Planting tanks with immersed and emersed vegetation can produce spectacular results with minimal effort. Plants that grow through the water and beyond its surface can purify the water column massively. A shrimp or two, a few snails, maybe a gecko, and you are set with a growing ecosystem.

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