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November Featured Fish: Molly

Molly fish

Molly fish are good for both beginner freshwater fish keepers and advanced aquarists alike. They acclimate easily to water conditions and have a fairly laid back temperament, making them good for community tanks.

Here’s what to know if you’re looking at getting mollies.

Multiple colors and varieties

Mollies are small fish that can really add a variety of colors to your tank. Types of molly fish include:

  • Black Molly
  • Black Lyretail Molly
  • Balloon Molly
  • Creamsicle Molly
  • Dalmatian Molly
  • Gold Dust Molly
  • Sailfin Molly
  • Green Sailfin Molly
  • Gold Calico Balloon Molly
  • Red Dalmatian Molly
  • Wild Molly
  • Silver Lyretail Molly

Balloon molly

Balloon Molly


Like many of the other small, mild tempered fish I’ve covered here, mollies are livebearers, meaning they bear live young rather than laying eggs. However, they have a fairly long gestational period compared to other fish. It’s about sixty days.

Note that although mollies are generally mild-tempered, if you put them in a community tank with other species, they can be semi-aggressive. They’ll be most calm in a tank with other molly fish.

Voracious feeders

Mollies are omnivores that tend to be easy to feed and will take almost whatever you give them, whether it sinks or floats. Bonus: they also like to eat algae from the tank, so they’ll help keep the aquarium clean.

Some things you can feed molly fish are brine shrimp, fish pellets, fish flakes, and fish granules.

Versatile water conditions

Molly fish can survive in either freshwater or saltwater conditions, and depending on where you get yours from, they may be used to hard or brackish water. When that’s the case, they can actually get some health problems if they’re put right into very soft, fresh water.

Dalmation molly

Dalmatian Molly

You can easily acclimate them to a freshwater tank, however, by adding Seachem Equilibrium, which makes the aquarium water “harder” (i.e., more full of minerals) or another water hardener.

Active swimmers

If you want an exciting aquarium, mollies are active swimmers that like to graze on algae. That also makes them excellent for putting into a live planted tank. They’ll love grazing on algae that might grow on the plants.

They can be energetic and semi-aggressive depending on environment and tank mates.

Gold molly

Gold Molly

What fish to put mollies with

Because molly fish can get aggressive, it’s best not to put them with especially docile fish, especially aggressive fish, or fish with long, flowing fins that might attract attacks.

Larger neon tetras or emperor tetras, as well as bristlenose plecos may be good tank mates. You can also put them with loaches and snails.

Mollies do best in slightly alkaline, hard water, so you’ll want to pick tank mates that can also thrive in those water conditions.

A note of caution

It’s always a good idea to keep new fish in a quarantine tank before adding them to a community aquarium, and this is especially true for molly fish, which tend to be more likely to carry “ich” (Ichthyophthirius multifiliis).

Ready for an interesting new fish? Come check out the mollies and other freshwater fish at The Tye-Dyed Iguana in Fairview Heights.