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9 Muppy Fish Facts! (Guppy Molly Hybrid Fish)

Although purebred guppies or mollies are still far more popular than the guppy molly hybrids, we have seen a spike in the attention that muppy fish or muppies are getting from aquarium keepers recently.

This has resulted in a wide range of questions being asked about muppies from the community so we have decided to publish this article going over the more common questions that we see people asking about.

Please note that although we have done our best to provide the most accurate information possible below, muppies are rare and like all hybrid fish, they can take more characteristics from either parent.

In addition to this, it is suspected that guppy molly hybrids can have a higher chance of various health problems than a purebred guppy or molly too with the effects of some of these health problems having a larger effect on how the fish will behave.

That said though, due mollies and guppies being very similar when it comes to their behaviour, the majority of the information below will be accurate no matter what.

One of the largest variables about muppies is how large they will be due to a molly often being around twice the size of a guppy and a muppy being anything in between and sometimes slightly larger than a molly.

Where Do You Buy Muppy Fish?

Muppy fish can be difficult to find due to how hard it is to breed them at a commercial scale. They are very rare in pet stores with any muppies you can find in a pet store usually being way overpriced.

This is why we usually recommend that our readers check specialist breeders online to check their muppy supplies and order the fish.

One of the cheapest ways to buy muppies is to check their availability on eBay as most of the people who breed muppies will usually offer them for sale on eBay prior to listing them anywhere else.

Even then though, there are large periods of time when there are no muppies available due to it being so hard to pair mollies with guppies to produce muppies.

There are some specialist breeding shows that will show various types of hybrid fish to show the various colors and patterns that the breeders have been able to achieve.

You can usually purchase muppies at these events but they tend to be very expensive due to being prize fish with rare colors and patterns rather than regular muppies.

What Do Guppy Molly Hybrid Fish Eat?

Muppy fish tend to do well on a diet based on a main food option of a flake or pellet based food with a live or freeze-dried food option being used as a treat.

There are a number of people who will only feed their muppies a flake or pellet based food without a treat option without having any issues due to diet though.

We usually recommend that our readers go with Tetra tropical fish food for the main food option for their pet muppies with the majority of muppy fish seeming to really enjoy it.

If you bred your muppies yourself then it also makes an excellent food option for the parent guppy and mollie fish too.

When it comes to offering live food as a treat, daphnia or brine shrimp are always excellent options with muppies really seeming to enjoy the taste while also enjoying chasing them around the aquarium and getting a little mental stimulation.

We know that many of our readers don’t like the idea of live feeding their fish so freeze dried brine shrimp can also be an excellent option too.

What Size Tank Does A Muppy Require?

Due to the size of a muppy being unpredictable and usually being anywhere between the size of a guppy or a mollie, we usually recommend that you go with a minimum tank size of 10 gallons for a muppy.

This will usually be large enough for three to five large muppies without them having any issues or becoming stressed due to the tank being too small.

Thankfully, there are some excellent 10 gallon tanks available that are very budget-friendly allowing all of our readers to pick up a high-quality 10 gallon tank if they are wanting to keep some muppies.

If you are wanting to keep more than five muppy fish then we would recommend that you try to go with a decent 20 gallon tank though.

This will offer up to 15 large muppy fish all of the space that they need to live a happy life. If the tank size is too small for your fish then you can run into problems with your muppies becoming stressed or anxious that can result in aggression and other potential issues too.

Do Guppy Molly Hybrid Fish Need A Heater?

Muppies really should be in a tank that does have a dedicated heather to help keep the water at a steady range of 70-85 °F throughout the day.

Keep in mind that this is the water temperature of the tank, not the ambient temperature of the room that the tank is in too with the actual water temperature being colder than the room temperature so if you live in an area with an average temperature of 70-85°F then you will still require a heater for your muppy tank.

Thankfully, due to muppies being happy in tanks of 10 and 20 gallons, they don’t require expensive heaters and you can usually get away with using a decent entry-level tank heater to keep your costs as low as possible.

This should easily be able to keep the smaller muppy tank options warm enough for them to be happy without you having to overspend on a heater.

Some people do keep muppies in much larger tanks though, especially if they are keeping a large number of muppies in their tank.

As you will probably know, the larger the tank, the larger the wattage requirement of the heater so your costs can quickly increase with the water volume of the tank you keep your muppies in.

Can Molly Fish Mate With Guppies?

Both mollies and guppies are from the Poecilia genus so are able to mate with each other successfully.

Just because mollies and guppies are able to mate with each other, does not mean that it is an easy task to achieve though and even then, a successful fertilisation is rare.

With molly and guppy fish both being from the Poecilia genus, they have the correct number of chromosomes to mate with each other but this does not always result in healthy babies.

As we mentioned back at the start of the article, muppy fish do tend to have an increased chance of health issues with all muppies being sterile and unable to reproduce themselves.

This lack of ability to breed a muppy with a muppy is the main reason that they are so rare as you always have the paid a molly with a guppy to produce a muppy.

Although there have been many attempts to produce a fertile muppy, to date all attempts have failed.

How Do You Breed Your Own Muppy Fish?

The most common method of breeding your own muppies is to add two male guppies to a tank with six female mollies in it and wait for them to breed.

Adding more guppies or mollies to the same tank can cause aggression to start, especially between the male guppies and this can reduce the chances of a successful pregnancy.

With mollies being livebearers, their fertilized eggs will actually develop inside of their body and they will release live fry once ready.

This works to your advantage when trying to breed your own muppy fish as it prevents other fish from eating their eggs and reduces the number of potential muppies that can be produced.

Ideal breeding conditions usually require the tank to be clean with water conditions such as the temperature and pH to be as close to perfect as possible.

As we mentioned earlier, the more fish in the tank can spike the stress and anxiety levels of the mollies making it harder for them to successfully carry their fertile eggs to term so we usually recommend a maximum of two male guppies per tank to reduce stress and anxiety.

Are Guppy Molly Hybrids Sterile?

To date, all guppy molly hybrids (muppies) have been sterile and this very common with hybrid animals. A number of breeders have put a large amount of time, effort, and money into breeding fertile muppies but so far, all attempts have failed.

If a breeder is able to produce muppies that can produce their own babies, we expect their population to expand rapidly with muppies being much easier to source if this ever does happen.

This can also help to bring the prices for muppies with the rarer colors and patterns to fall drastically due to there being more muppies available.

At the time of writing though, all muppies are produced by directly pairing a molly with a guppy making muppies rare and keeping their prices higher than usual.

Although there are a number of breeders who are producing more and more muppies with each year that passes, it is notoriously difficult to produce muppies in large numbers even when trying to specialise in their production.

Are Muppies Aggressive?

Muppies tend to be passive similar to both of their parent species, the guppy and the molly but keeping muppies in a tank that is too small or is overcrowded can result in them displaying signs of aggression.

This is why we recommend that you go with a 10 gallon tank minimum for your muppies with a 20 gallon tank usually being the best option for most people.

Muppies do tend to defend themselves if other fish species are aggressive towards them too so keeping them in an aquarium with other non-aggressive tank mates is often a good idea.

Just like guppies and mollies, a muppy tends to do very well with suitable tank mates in a tank that is large enough to give it room to swim around as it likes.

If you do choose to live feed your muppies something like live daphnia or brine shrimp then don’t mistake your muppies chasing the daphnia or brine shrimp as aggression to each other.

This is a common mistake when the fish are usually just swimming to catch the live food that you have given them rather than actively being aggressive toward each other, once all of the live food has been consumed, they will usually return to their normal behaviors.

What Does A Muppy Fish Look Like?

Muppies tend to have the head of a guppy with the body of a molly and range in size from that of a guppy to that of a molly.

Color and pattern wise, muppies can pull from either their guppy or molly lineage resulting in some very unique looks for the fish with rare looks being able to command a high price.

Although some people think that the price of rare colored muppies will be low due to the fish being sterile, the fact that muppies are sterile prevents selective breeding too.

This means that each muppy that is born is a fresh roll of the even dice and can be any color with any pattern. This helps to keep the costs of rare looking muppies as high as possible with many collectors paying over the odds for rare colors.

Although rare, a muppy fish can have the head of a molly and the body of a guppy but it is far more common for it to have the head of a guppy and the body of a molly.

It tends to be about an even split for the tail of a muppy with each fish usually having a 50/50 chance of having the tail of a guppy or the tail of a molly.


That brings our guide to muppy fish (guppy molly hybrids) to an end. We hope that we have been able to answer any questions that you had about muppies to help you better understand the fish species. Although the muppy is a rare fish with low levels of popularity and interest, it is increasing in popularity with each year that passes and we only expect this to continue for years to come.