Guppy Fish and Molly Fish – Are They Good Tank Mates?

Guppy fish and molly fish are both peaceful fish. They are two of the most popular types of freshwater aquarium fish to keep as pets. There are many types of guppies as well as many types of mollies. Both fish are livebearers which means that they do not lay eggs but give birth to live young. So, can you keep guppy fish and molly fish in the same aquarium? Yes. You can keep guppies and mollies in the same tank. Both are peaceful fish and generally will not attack each other. They also eat the same food. The perfect tank mates. However, there are instances where it has been reported that adult mollies will harass and attack guppies.


Feeding your molly fish and guppy fish is easy. Things like live food, cocked vegetables, frozen food such as blood worms, freeze-dried food, veggie pallets, spirulina, etc. are ok.


Both guppies and mollies give birth once every 30 days. The only problem is that both fish are known to eat their fry. Thus, it is a good idea to remove the fry from the adult tank. Raise the baby fish in a separate tank until they too big for the adults to eat. You can place the female in a separate tank until she gives birth and return her to the main tank once she drops her young. It’s easier to this than to try to remove the baby fry from an adult tank. If you don’t have a separate tank, you can increase the chances of survival for the young fry by adding live plants to your tank. The plants offer hiding places for the fry. The young fish feed on algae, leftover food, etc. and generally hide until they are big enough to venture out in the open.
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Water Conditions

Mollies and guppies are a type of tropical fish thus they both live in the same water conditions. To keep it as natural as possible, you can opt to have a brackish water tank. A weekly 30-50% water change is enough for most aquariums. However, for overpopulated fish tanks, you need to monitor the ammonia levels and make more frequent water changes.


Molly fish can save sperm for up to 3 months. Guppy fish can save sperm for a lifetime. This means that both fish can reproduce using sperm from a previous encounter with a male. Both fish are prolific breeders. It can be hard to control the fish population in your tank under these conditions but a good way to reduce the birth rate is to keep only males of the species in your aquarium. Other than that, keeping guppies and mollies together is no problem at all. External resources:

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