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Can You Put A Betta Fish With Mollies?

Over the last couple of decades, betta fish has skyrocketed in popularity to become the most commonly kept freshwater fish amongst fish keepers and the popularity of bettas is seeing another surge right now due to the unique and rare looking betta fish being cheaper than ever.

Although betta fish can be a great option for people of all levels of experience, we often see people reaching out and asking questions about suitable tank mates for betta fish.

With mollies being another very popular fish that can work well for fish keepers of all levels of experience, we have noticed a number of people reaching out and asking if you can put betta fish with mollies in the same aquarium recently.

Although most of the discussions on social media asking about this are usually given a simple yes or no answer, it is not as simple as this due to the aggression level of bettas and the fact that mollies need to be kept in groups of at least four mollies to feel safe.

This is why we have decided to publish our own dedicated article on the topic in the hope that we are able to clear up some of the common mistakes that we see people making when they try to mix betta fish and mollies in the same tank.

Not only will following our pointers below make it much easier to keep your fish in the same tank but it will also make it easier to keep your fish happy and prevent displays of aggression from your betta fish.

Can You Put A Betta Fish With Mollies?

Most people new to fish keeping should keep their betta fish in its own tank but as your experience with keeping fish increases, you are able to upgrade your tank size and add other fish to the setup including mollies.

As you will usually need a minimum of four mollies due to them being a schooling fish, you will usually need a tank that is between 40 and 55 gallons to have four mollies and a single betta fish in the same tank.

Even then there may be some problems with aggression if you go with the 40 gallon aquarium and have a male betta fish but the 40 gallon tank with a female betta fish and four mollies can work.

Ideally though, you should be trying to go with a 55 gallon aquarium if possible when looking to mix mollies and betta fish in the same tank as it offers the fish plenty of space to keep problems with aggression to an absolute minimum.

If you want to keep more mollies in the aquarium or a betta safe algae eater then you will need to increase the tank size even further with a 75 gallon aquarium being recommended for more than 4 mollies with a single betta fish.

This is a very popular tank size for keeping betta fish with any type of schooling fish as it allows you to keep a large number of the schooling fish in the tank while your betta has plenty of space to do its own thing without being aggressive.

Tank Decorations For Keeping Betta Fish And Mollies Together!

You should always keep plenty of fish hides and plants in any tank that has a betta fish with other tank mates as it breaks line of site and can offer plenty of places to fish for both species.

This can help to reduce the chances of any outbreaks of aggression between the fish due to the mollies having various areas in the tank where they are able to go that is out of sight of your betta fish.

These days there are plenty of excellent fish hide options on the market that you are able to use in your tank.

When it comes to plants you are able to go with some zero maintenance fake plants or live plants such as java fern to offer plenty of cover and hiding places in your tank for the fish.

People often underestimate the benefits of fish hideouts and plants for betta fish too. Although they can be aggressive at times, bettas seem to appreciate the fish hides and plants to be able to hide in and relax just as much as their tank mates too.

This is why we consider this type of decoration that has a practical application an essential addition to any tank with bettas in even if the betta fish is the solo occupant.


That brings our article going over if you can put betta fish with mollies in the same tank to an end. Although it can be done, it usually required an aquarium larger than what the majority of our readers usually have. This is why we often just recommend that you keep a solo betta fish in a 5-10 gallon tank until you build up some experience in the fish keeping hobby to where you feel confident and have the budget available to maintain a larger tank that will be suitable for keeping betta fish and mollies together.