Fish In A 20-gallon Tank

A 20-gallon fish tank could be a great additional display in the living room. It simply shows a glimpse of the beauty that lies in the underwater world.

But a 20-gallon tank can be too little for the fish, especially those who have territorial problems. An overcrowded fish tank will create problems like a dirtier environment, territorial fights, and stress.

What’s included in a 20-gallon tank is a variety of live plants that may add to the aquarium’s beauty. If you desire to make the fish aquarium a bit interesting, then never overcrowd them. It is because you might be losing one fish and another if you’ll stick them in one place.

Choose the best fish that can live with each other in a small room, and that’s where research will come in to help you with your decisions.

Every fish deserves a place to breathe properly, swim freely, create too little ecosystem for them, and be overpopulated. It might be the reason for your fish’s sudden death.

Consideration About Fish’s Physiology

It would be helpful if you consider some fun facts about fish, especially since not all have the same temperament and comfort zones. Fish, like fighting fish, live up to their name as they are fighting to what they consider their own.

There are many aggressive, predatory, and community kinds of aquarium fish, but it is more important to match their temperaments to avoid killing each other. Another example, if you placed a predatory fish full of community fish, then expect that no community fish will ever survive.

Another factor that you have to consider is the pH requirements and temperature comfortable for the fish. When it comes to pH level, tropical fish can adjust to it very easily, while cold-blooded fish have their specific range of pH levels.

As for the temperature, goldfish is the most versatile because it can adjust its body temperature to the water temperature. Last to consider and the most important is the size, simply because bigger fish eat the little ones.

Top 5 Fish That You Can Keep In A 20-gallon Aquarium

What’s written on the list are the community fish that are mostly at peace with each other. They can get aggressive in some situations, but they are primarily compatible with other fish species.

Dwarf Gourami

Dwarf-Gourami is the only fish that can get semi-aggressive at times, but they can be a great companion to the other fish most of the time. However, they wanted to be one of his species in the tank.

If you put 2 Dwarf-Gourami of the same sex in a tank, they will bully one another. If just in case that this may happen, add a place for the other one to run and hide unto.


Guppies are the peacemaker in every fish tank and have no problems when being stuck with another fish. They have the brightest scale and, fortunately, the smallest, so they won’t get involved themselves in a fish fight, only except you pair them to a predator fish.


Otocinclus is also called the shoaling fish. Although they are small in size, they are big eating of algae and other microorganisms found in the tank. They also look like plecos because of some similarities to their character.

Otocinclus loves to kiss and stick to the glass aquarium and interact with those who see them. The only difference that they have with plecos is a dozen otocinclus can stay in a 20-gallon aquarium.


Molly fish have many varieties, but the best aquarium fish to keep is the black molly. Molly fish don’t lay eggs when giving birth to their offspring. That means, one day, you may wake up one morning for additional fish around your tank.


Swordtails are different from swordfish. As mentioned above, one of the most territorial fish is the swordfish. At the same time, the swordtails are just as funky and peaceful.

Swordtails are commonly compared to platies because of their appearance and behavior, except that the swordtails have an imbalance and longer tail.

Big Fish For Your 20-gallon Tank

If you consider petting a bigger fish than these five listed above, you might want to update your rule to have only one fish per 20-gallon tank. For big fish, this is too crowded if they are placed together. They needed more space where they can swim.

The best 20-gallon tanks today arrive with the most durable materials, such as Tetra 20-gallon Aquarium. You may also want to get the most out of the simplicity and functionality of the Aqueon Aquarium 20 Gallon.


While some people didn’t realize that angels can grow a lot like adults, and they will feed on the younger and smaller ones such as guppies and tetras.


Goldfish can be pretty specific when it comes to their needs, and with them being not nice to other fish species, it’s okay only to put one goldfish in a tank. They can get huge but not as large as the Koi fish. Goldfish can easily adapt to their environment and temperature, too.


The older gourami gets a little bigger. However, they can still be the same as before: semi-aggressive. The same rules for gourami may apply, but because of their massive growth, then you might just put them in a larger environment.

For large gourami, they also do not like it when they have same-sex companions in the same environment.


Fish have different sets of attitudes that you should take note of, and since you want to take care of them, then live to it at the maximum. If a 20-gallon is not enough to tank for you to handle, then invest in a new, larger fish tank.

What’s important is that you have managed to research the specific needs of your pet fish, especially in the area of temperament and social interaction.

Add and support to have aeration and filtration to the fish so your fish can breathe in it, and whatever they intake will be safe and healthy for them.