How Many Fish Can You Put in a 10-Gallon Aquarium

The scary thing about overcrowding in an aquarium is that it isn’t only about numbers – combining the wrong types of fish could also lead to adverse results.

You can have dead fishes in your 10-gallon tank if you choose wrongly. Understanding the needs and temperaments of fishes is the key to selecting candidates for your fish tank.

A 10-gallon tank gives a chance to create a vibrant ecosystem of fishes teeming with life. But how do you know how many fishes are adequate for a 10-gallon tank?

There’s a lot to consider here.

It would be best if you didn’t only listen to the staff at your local pet store as some might not have all the information. Also, you need to look beyond size.

We have compiled a list of the best options for a fish tank, a relevant guide to help you set up, and a FAQ section.

Let’s dive in!

Guidelines for Stocking Your 10-gallon Aquarium — The Ideal 10-Gallon Fish Tank Setup

Before adding fish to your new tank, we recommend that you take a few preparatory steps to make it suitable for your fish.

Steps in Setting Up the Tank

Step 1

Put the gravel in a bucket and run water through it as you rub it with your hands to clean and remove all impurities. Keep on with this process until the water is clear. Gently add a layer of about 0.5-1 inch to the tank.

Step 2

Gather the decorations you want to put in the tank and rinse them under running water. Put them in the tank before adding the water to maintain a reasonable water height and avoid an overflow.

Step 3

Put a water conditioner/dechlorinator in the water to remove the chlorine in the water that will be harmful to your fish. For a 10-gallon tank, 1ml should be enough but check the bottle for confirmation.

Step 4

If you are preparing a marine tank, you’ll also have to fix up artificial saltwater. Go to a pet store and buy sea salt and purified water to start the process. Keep the water idle for at least a day so the salt can dissolve properly.

Step 5

After your water is in the tank, you’ll have to install your filter. Depending on the fishes you intend to keep, you might also install a heater.

Step 6

Rinse off the internal material of the filter under running water before installing it in your setup. Check the filter’s manual for the installation instructions to guide you through this step.

Step 7

Start the cycling process by adding about 2-4 parts per million (ppm) of ammonia and 1ppm in subsequent days. 

Step 8

Use a water testing kit to check the water for the ammonia, nitrite, and nitrate levels weekly.

Step 9

After two weeks, you should notice a spike in the nitrite levels, and the bacteria should begin converting the nitrite to nitrate.

Step 10

As soon as the ammonia and nitrite levels are at 0ppm, it means the cycle is over, after which you can add fish to your aquarium slowly.

Who Should Get a 10-Gallon Aquarium?

A 10-gallon tank is a small tank and is an ideal way to start your journey into fishkeeping. These tanks are suitable for beginners because they are easy to handle, inexpensive, and portable.

Anyone looking for a tank with fun and educational benefits can go for a 10-gallon tank.

However, we observed that where people seem to make the most mistakes is selecting the fishes for a 10-gallon tank. Ideally, the most important factors are the size of the fish, behavior, and nature (territorial or aggressive).

A common rule that fish-keepers often pass around to guide newbies in selecting fishes for their tanks is the “one inch of fish per gallon” rule.

Now, we are telling you that this doesn’t work in all cases, as some species will need more space than others.

So, here is our recommendation.

Top 7 Fishes for 10-gallon Aquarium — Fishes that are Compatible in a 10-Gallon Tank 

1. Corydoras

Corydoras or Cory catfish are small bottom breeding fish that grow to only 2-3 inches in length. Their size will make them a perfect addition to a 10-gallon tank. Also, they’re peaceful with other species and enjoyable to watch.

These fishes can also serve as a clean-up crew. Since they’re bottom feeders, they mostly depend on food that falls to the bottom of the tank.

They will generally scavenge anything they can find. However, you should also feed them sinking pellets so they get adequate nutrients for growth.

Pro Tip:

Keep at least 6 of them if you want them at their happiest.

2. Neon Tetra

Neon tetras are flashy fishes that will attract a lot of eyes to your aquarium. One of the most popular fishes for a freshwater aquarium, their iridescent blue bodies and bright red stripes are highly-recognizable.

They are relatively inactive fishes that will not trouble others except they are stressed, which makes them nippy with each other.

Neon tetras grow to about 1.25 inches in length and prefer an aquarium with plenty of plants so they can hide. Adding rocks and driftwood to your tank is also a good idea as it will closely resemble their natural habitat in the clear streams of South America.

Pro Tip:

If you want a neon tetra-only tank, you can apply the one inch of fish per gallon rule here and get 10 of them for your tank.

3. Guppies

Guppies are one of the easiest fish to care for, and they are part of our standard recommendations for a beginner. It would be best if you got varieties of this peaceful fish with the male having more options than the females. 

If you’re setting up a breeding tank, this fish will not give you any trouble, as they can quickly breed without assistance. You’ll have a lot of fun watching Guppies play around in your tank.

You may not need many plants or decorations if you’re keeping them because they swim actively in the top third of the water column. 

Pro Tip:

Don’t get males and females or they will breed and fill up your 10-gallon tank in no time.

4. Dwarf Gourami

The Dwarf Gourami might not be ideal for beginners, but fish keepers with previous experience will have no problem with it. The males have an orange-looking color with blue vertical stripes, and the females have silvery blue-gray colors with faint yellow lines.

There is a chance that they may pick on each other as gourami are semi-aggressive fishes. So, you should have decorations and plants in your tank that will serve as hiding spots if one of them becomes dominant.

These fishes only grow to a length of 1.5 inches, so you will have no problem pairing them with other fishes.

Pro Tip:

Your tank should be in a quiet area because loud noises can scare them easily.

5. Golden Dwarf Barbs

Although not as popular as the other Barbs species, they will make a perfect addition to your 10-gallon tank. This freshwater fish only grows to about 1.5 inches – meaning other fishes can fit in the same tank.

You can quickly identify these fishes by their bright golden-yellow colors with black markings running along their body. They thrive in planted aquariums that also have driftwood and floating plants so they can play and hide.

Golden dwarf barbs coexist well with other species and are great companions for small species like Trigonostigma.

Pro Tip:

It would help if you kept them in groups of at least five, and you shouldn’t exceed keeping 10 in a 10-gallon tank.

6. Betta fish

Even though they are notorious for being the fighters in an aquarium, you can still make them work in a 10-gallon tank. As long as you understand their behavior and nature, they can thrive with other fishes in a community tank if you do proper research.

However, your best bet is keeping them as a single setup – one betta for a 10-gallon tank. Under no circumstances should you put two bettas in the same tank as they could become aggressive with themselves. Some people opt to keep them in bowls, but they’re better suited for planted tanks.

Pro Tip:

If you want to put betta fish in a community tank, avoid placing them together with similar species such as Guppies.

7. Celestial Pearl Danios

Danios are a perfect addition to a 10-gallon tank because of their small size (1 inch) and peaceful nature. Beginners will also have no problem with these fishes as they are easy to care for, and almost anyone will get the hang of them in no time. 

Celestial Pearl Danios are easily identifiable by their deep blue metallic body. The jewel-like spots and horizontal orange bands on their fins also give them a unique appearance.

They thrive better in planted aquariums that have lots of caves, driftwood, and rocks. Please keep them in a school with at least six members for the best results.

It may interest you to know that they’re excellent tankmates with Cherry Shrimp.

Pro Tip:

Even though the community discovered these fishes in 2006, they are one of the best choices you can pick for a 10-gallon tank.


How do I add fishes to a 10-gallon aquarium?

You should add fishes into the tank one at a time so that the bacteria are not overwhelmed with the waste.

  • Firstly, use a thermometer to check the temperature by placing it as far away as possible from the heater and leave it for some time. 
  • Check the reading to ensure it isn’t harmful to your fish before putting them in the water.
  • Turn off the aquarium light and float the plastic bag with the fish on the water surface for 15 minutes so it will adapt to the tank’s temperature.
  • Open the bag and add half a cup of tank water to it every 15 minutes for 1 hour. This will make them adapt to the other conditions of your water.
  • Use a net to remove the fish from the bag, put them in the tank, and take away the bag without allowing its water to enter your tank.
  • Keep the light off for a few hours for the fishes to settle in.

What variety of a 10-gallon tank should I get? 

There are two main options available when selecting 10-gallon fish tanks – glass or acrylic.

Glass aquariums are more durable and resistant to scratch than acrylic. Hence, they are usually the better option for many aquarists. Glass tanks also retain good clarity over time, far more than acrylic tanks, so they will be excellent for long-term use.

On the other hand, acrylic tanks weigh less than glass, and you should consider getting them if you’re unsure about the strength of your aquarium stand.

We advise you to take extra care when cleaning the sides of acrylic tanks to confirm the product is acrylic-safe and the substrate does not get to the middle of the scrubber and acrylic.

Which tank is better?

The popularity of glass tanks has made them the cheaper option of the two, and we would recommend a glass tank over acrylic.


Ultimately, the most important factors to consider in selecting fishes for your tank are fish species, plants/décor in your tank, and personal preference.

Regardless of the fishes you select for your tank, prepare it weeks before putting the fishes inside so your ecosystem stays balanced. Also, put fishes into the tank gradually, as we explained above, so they have time to adapt to the surroundings.

The key to keeping a happy tank is remaining consistent in your care and regularly updating yourself about your fish’s needs. Don’t get caught unaware by over-population challenges.

You can check out more articles to learn how to prepare yourself before buying an aquarium on

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