Can You Keep Mollies With Discus?

Technically speaking, you can keep mollies and discus together in the same tank since they’re both calm and peaceful fish, but you’ll need to provide a large enough tank and lots of hiding places. That said, your mollies and discus still may not get along and end up in aggressive confrontations. If this happens, you should separate the two fish as soon as possible.

Mollies are one of the most popular fish among beginners in the hobby thanks to being docile by nature, low maintenance, and hassle-free to breed. They come in multiple types -with color variations of orange and black- and possess unique characteristics such as being livebearers and algae eaters.

Discus fish are one of the most valuable species in a freshwater aquarium not only for their peaceful nature and wide range of exquisite colors, but they’re also rather expensive. These fish are also known for being quite timid and shy, so they do well alone but you may not see a lot of them often.

With such two interesting tropical fish, you may be wondering whether or not they can stay in the same tank. In today’s article, we’re answering the question “can you keep mollies with discus?” by discussing their behavior and tank requirements.

Red Molly Fish Fish

Can You Keep Mollies with Discus?

As we mentioned above, you can technically keep mollies and discus together in the same tank as long as you provide a large enough aquarium and choose species that demand water conditions as similar as possible.

Generally, both mollies and discus are docile and friendly fish by nature. This makes them relatively compatible as tank mates.

However, mollies and discus getting along isn’t a guarantee. They may end up in aggressive confrontations, where the mollies disturb the discus or vice versa.

To keep any fish species together, you should first check that they share more similarities than differences. This doesn’t just include the fishes’ temperament and behavior, but also their tank requirements such as water conditions and environment setup.

This is where carefully choosing molly and discus species becomes crucial. For example, common mollies don’t need as much salt as sailfin mollies, which makes the former a bit more suitable for the softer water hardness recommended for discus fish.

If you don’t invest some time into selecting appropriate species, you may end up with fish that are too different to live in peace.

For example, discus are known to be shy fish with more strict demands for water quality. If you place them in an environment that favors the mollies or the other way around, this can cause stress for the fish and make them prone to hostility.

Also, if you pair an outgoing male molly with a shy discus, the former may harass the latter and cause it to hide for prolonged periods. Similarly, wild-caught discus can get quite aggressive with more docile mollies.

In such cases, you should separate the two fish as soon as possible, or try to alter the tank conditions to achieve a balanced environment that can better house both species.

Karelj [CC-BY-SA-3.0]

Can Molly Fish Live with Discus Fish?

The answer comes down to the species you choose and the tank you provide. Below are some important aspects to consider:

Water Parameters

Although they aren’t as picky as discus when it comes to how they like their water, mollies can still be tricky to get their water conditions right.

Part of this is because they’re available in various species and another part is because some of them -as livebearers- love salt very much. Examples of such mollies are sailfin mollies and Yucatan mollies.

  • Sailfin mollies can’t do without salt in their tank water as pure freshwater can eventually kill them due to opportunistic diseases or make them stop eating and die out. The more salt you add to their water, however, the more they thrive.
  • Yucatan mollies are very close cousins to sailfin mollies and have nearly identical appearances. They also share the same love for salt, thriving in it and wasting without it.

For both mollies, 4 or 5 tablespoons of salt per gallon can be just enough to meet their requirements without being too much for discus fish that don’t necessarily need salt.

That said, a better option would be opting for common mollies as they’re much more adaptive to the absence of salt and can live in pure freshwater without catching diseases or dying.

As for discus fish, they aren’t very tolerant of unfavorable water quality.

They require pristine water with strict conditions such as a pH between 5 and 7 (no more than 8) and temperature below 86 degrees F. Discus also thrive in soft water with hardness less than 4 dKH.

Aquarium Setup

This is one area where molly and discus fish are pretty similar. They both do well with sandy substrates that allow for burrowing around to pick up grains of food.

Both mollies and discus also enjoy playing and especially hiding away, so it’s a good idea to add some tall plants and ornaments like rocks where they can seek shelter and hide when feeling shy.

For the sake of the discus fish, make sure that the aquarium supports good filtration. You should also place the tank about 3 to 4 feet above the floor to help your discus feel safer.

Can You Keep Mollies and Discus with Other Fish?

Adding tank mates depends on the size of the aquarium as well as its condition.

With the more demanding discus, you should choose fish that can live in their environment, not the other way around. As for mollies, they’re more adaptive so they can live peacefully with many types of fish as long as they aren’t aggressive species.

Examples of tank mates that are compatible with both molly and discus fish are angelfish, tetras, and snails.

Wrap Up

So can you keep mollies with discus? The answer is yes if your discus isn’t wild-caught and you choose a molly species that can live in the water conditions required for the discus.