Yes, they can. Some people avoid betta fish because of their violent tendencies.
The so-called fighting fish can make life a living hell for their neighbors, especially when you house them in small, crowded, poorly maintained spaces.
But Mollies are larger than betta fish. They are strong enough to fight back if the need arises. As the guide below will soon reveal, mollies are the perfect tankmates for betta fish.
Can I Keep Molly Fish And Betta Fish Together In The Same Tank?
Molly fish and bettas tick all the right boxes. First of all, they thrive in similar water conditions.
Secondly, they eat the same food. Third, the size difference is too small to matter. Admittedly, you can’t ignore a betta’s violent tendencies.
But you can prevent unnecessary conflicts by maintaining a pristine tank with the correct parameters and plenty of hiding places.
You should also acclimate the fish carefully during their introduction to the molly fish aquarium.
If the tank is brand-new, add the mollies first. Give them a chance to establish their territory.
Some aquarists will turn the lights off for hours after the betta fish enters the aquarium to protect them from unwanted attention.
Because fish have distinct personalities, and some may choose to lash out without provocation, observe the aquarium. Don’t hesitate to remove new fish that refuse to behave.
Also Read: 19 Great Molly Fish Tank Mates
Molly Fish vs. Betta Fish: Natural Behavior
Mollies and bettas are an interesting combination because one species is peaceful while the other has aggressive tendencies.
Surprisingly, this is a solid pairing. You don’t respond to violent fish by giving them equally violent neighbors.
The creatures will fight incessantly until they die. The best option is a large but peaceful fish strong enough to keep aggressive neighbors in check.
You get that pairing when you place mollies and bettas in the same aquatic space.
Molly Fish: Natural Behavior
Mollies are shoaling fish. While you won’t see them swimming in synchronicity with their kind, they prefer to live in groups with other mollies.
This speaks volumes about their personalities. Mollies are social and friendly, and they tend to behave when you pair them with equally peaceful fish.
Aggression in this species is a sign of fear and stress. If your mollies keep lashing out, investigate the tank until you identify the factors compelling them to misbehave.
Betta Fish: Natural Behavior
Betta fish are misunderstood. Are they aggressive? Yes, they are. The fish are highly territorial.
However, they usually fight other bettas, particularly the males, which is why keeping multiple male bettas in the same aquatic space is discouraged.
If you want multiple bettas, stick to the females. While they can also lash out, female bettas tend to tolerate one another.
What if you want to breed this species? Add one male betta and multiple females. A male betta can harass a female betta to death.
Increasing the number of females protects the fish by diluting the male betta’s attention.
As far as the betta’s relationship with the molly fish is concerned, mollies are strong enough to defend themselves against a male betta’s antics.
Ideal Parameters For Molly Fish And Betta Fish
| Parameters | Temperature | pH | Hardness |
| Molly Fish | 75 to 80 (F) | 7.5 to 8.5 | 12 to 25 dGH |
| Betta Fish | 75 to 80 (F) | 6.5 to 7.5 | 5 to 15 dGH |
Molly Fish: Ideal Parameters
Molly fish are tropical creatures that thrive in warm conditions, hence the 75 – 80 F temperature range noted above.
Their water bodies in the wild have a high mineral content. Try to replicate these conditions by adding substances such as crushed coral to make soft water hard.
Don’t allow the parameters to fluctuate. This is why heaters are so important.
While some aquarists can do without them, they are vital to people in regions with volatile weather conditions.
Mollies are hardy enough to tolerate the wrong parameters. But forcing them to withstand poor conditions exposes the creatures to stress and potentially fatal diseases.
Betta Fish: Ideal Parameters
A betta fish’s parameters are practically identical to those a molly fish enjoys, particularly the temperature (75 to 80 degrees F).
You can add a betta fish to a molly fish tank without changing the parameters. The bettas will fit right in.
But again, proper acclimation matters. Otherwise, the shock from the transition may kill the bettas, especially if the water has a high salt content.
Molly Fish vs. Betta Fish: Ideal Water Conditions
| Requirements | Molly Fish | Betta Fish |
| Ammonia | 0ppm | 0ppm |
| Nitrite | 0ppm | 0ppm |
| Nitrate | Less than 20ppm | Less than 20ppm |
| Tank Size | 20 gallons | 10 – 20 gallons |
| Foliage | Yes | Yes |
| Decorations | Yes | Yes |
| Filter | Yes | Yes |
| Heater | Yes | Yes |
| Salt | Maybe | No |
Molly Fish: Ideal Water Conditions
Molly fish can tolerate the conditions you find in conventional tropical aquariums. Their needs don’t differ from those of other tropical creatures.
They require a filtration system, regular water changes, and hiding places. The only significant concern is the salinity.
Consult your retailer to determine whether your mollies need brackish conditions. The conditions in which the molly fish was reared will decide whether or not it needs salt.
Betta Fish: Ideal Water Conditions
Bettas live in rice paddies in the wild. They are accustomed to having plenty of hiding places.
Help them by adding natural or artificial plants and decorations such as caves and driftwood. Stay away from sharp objects that tear fish fins and scales.
Artificial lighting isn’t necessary if the room has a reliable source of natural light. If you prefer artificial lighting, create a regular day/night cycle.
Filters are necessary to keep the water clean. Don’t overwhelm the fish with fast-flowing water. The stress will kill the bettas.
Don’t forget to rinse the mechanical filter once a month. Any aquarium that accommodates molly fish will keep the bettas happy. They don’t have unique demands and requirements.
The Dietary Requirements Of Molly Fish And Betta Fish
| Food | Molly Fish | Betta Fish | Quantity | Schedule |
| Fish Pellets and Flakes | Yes | Yes | Small Pinch | 7 Days |
| Tubifex Worms | Yes | Yes | Small Pinch or Less | 2-3 Times Weekly |
| Bloodworms | Yes | Yes | Small Pinch or Less | 2-3 Times Weekly |
| Brine Shrimp | Yes | Yes | Small Pinch | 1 – 2 Times Weekly |
| Vegetables | Yes | Yes | Small Pinch | Twice Daily |
| Daphnia | Yes | Yes | Small Pinch | 1 – 2 Times Weekly |
| Mysis Shrimp | Yes | Yes | Small Pinch | 1 – 2 Times Weekly |
| Maggots | Yes | Yes | As much as they can eat in three to five minutes | 2- 3 Times Weekly |
| Fish Fry | Yes | Yes | No limit | The Fish will eat the fry whenever they see fit. |
Molly Fish: Ideal Dietary Requirements
Mollies are not picky. The omnivores will eat whatever you give them.
Try to balance their meals by mixing flakes and pellets with organic foods such as worms, shrimp, and mosquito larvae. Stick to one or two meals a day.
Mollies are unlikely to fight their neighbors for food.
But if they occasionally clash with the bettas during mealtimes, spread the food throughout the tank. Don’t force the fish to eat from the same location.
Betta Fish: Ideal Dietary Requirements
Betta fish and mollies eat the same meals. They require a combination of animal and plant matter.
Newcomers should stick to flakes and pellets because these products have clear dosing instructions. You are less likely to overfeed the creatures.
As you accumulate experience, you can experiment with live, freeze-dried, and frozen foods.
Ideal Tank Size For Keeping Molly Fish And Betta Fish
Twenty gallons should be the starting point.
While bettas can live alone, you need five fish or more to keep the mollies happy. If you’ve decided to keep both species in large groups, aim for 29 to 55 gallons.
Best Tankmates For Molly Fish And Betta Fish
If you’re seeking to diversify your aquarium, having only mollies and betta fish may become tedious.
However, if your tank can hold 20 gallons or more, there are alternative choices available.
Here are a few tranquil species that can coexist harmoniously in your tank:
- Swordtails
- Guppies
- Angelfish
- Platies
- Ghost Shrimp
- Kuhli Loaches
- African Dwarf Frogs
- Harlequin Rasboras
- Panda Corys
- Mystery Snails
Also Read: Do Mollies Eat Snails?
Fish To Avoid With Mollies And Betta Fish
On the other hand, it’s best to avoid adding aggressive species. I strongly discourage including:
- Gouramis
- Tiger barbs
- Angelfish
- Dwarf cichlids
- Rosy barbs
- Serpae tetras
- Redtail shark
- Goldfish
Also Read: Can Mollies Live With Goldfish?
Conclusions
For those of you in a rush, here is brief summary of what I discussed earlier:
- Molly fish and betta fish can live together in the same tank if the proper conditions are met, such as maintaining a clean and spacious environment with hiding places.
- Mollies are larger and strong enough to defend themselves against bettas, making them suitable tankmates.
- Molly fish are social and friendly, while betta fish have aggressive tendencies, but their combination can create a balanced and peaceful aquatic space.
- Both molly fish and betta fish thrive in similar water conditions, including temperature, pH, and hardness levels.
- It is important to provide the ideal water conditions, dietary requirements, tank size, and compatible tankmates to ensure the well-being and harmony of both molly fish and betta fish.