How to Tell if a Molly Fish Is Dying? Let’s Get The Answer!

Although mollies are incredibly hardy fish, they’re not invincible. Their average lifespan is about two to five years, depending on the care you provide.

Of course, mollies can die earlier than their expected lifespan for various reasons. So, how to tell if a molly fish is dying?

As an aquarist, you may wonder about many questions. The article will provide you with useful information about this problem. Keep reading to find out!

How to Tell if a Molly Fish Is Dying?

Dying mollies may display all or the combination of the following signs:

  • Pop-eye
  • Lethargy
  • Sickly odor
  • Fins falling off
  • Swollen gills
  • Loss of appetite
  • Minor brown spots
  • Change in coloration
  • Crash at the bottom of your tank
  • White specks appear on fin skin

black mollies

Signs of a dying molly fish


Almost all diseases and illnesses in mollies can lead to pop-eye. It refers to when your mollies’ eyes pop out from the socket because of fish TB,  bacterial infections, dropsy, internal parasites, or fungal infections.

Swollen Gills

Mollies may have swollen gills if they have difficulty getting oxygen or breathing heavily. If this condition persists, they will die.

Change in Coloration

If your Mollies lose colors, the cause may lie in unclean water. Molly fish which live in an overpopulated tank can be more likely to fade their usual color.

Fins Falling Off

If you notice your mollies’ fins are falling off, you need to take care of them as soon as possible as they may be dying.

It can be due to stress caused by environmental changes. But sometimes, their fins will fall off without reason.

Crash at the Bottom of Your Tank

Healthy mollies do not swim near the bottom in most cases. But if your fish are showing this sign, they may be struggling with health issues.

Bladder problems cause them to sink to the bottom of the tank due to their inability to control their buoyancy.

Mollies with bladder problems also have difficulty staying upright and eating.

White Specks Appear on Fin Skin

White Specks on molly

White specks might be a sign of protozoan infection

It might be a symptom of protozoan infection. Protozoa in mollies may come as one result of poor water conditions.

Sickly Odor

A sickly odor from your aquarium can also indicate that your mollies are dying.

This odor shows that bacteria are growing inside your tank while your fish can’t survive anymore.

Moreover, mollies need the proper amount of oxygen to live, while too much ammonia from other fish will make your mollies sick.


Lethargy is one of the other symptoms that your mollies are dying from illness or old age.

The most obvious sign is that your fish seem lazy for a long time and don’t move around often.

Loss of Appetite

Mollies will stop eating if they are dying or sick. So eating less or not preferring food may tell if they’re fighting illness for an extended period.

When you notice your mollies stop eating, there are probably issues in your aquarium.

Hence, we recommend checking out all other possibilities before diagnosing health problems.

Minor Brown Spots on Mollies

This symptom may occur because of parasites like anchor worms.

Is It Possible To Treat Dying Mollies and Save Them?

molly fish swimming

You can treat some symptoms at home

The treatment of your mollies will depend on the severity of the condition and the cause.

It is possible to treat some conditions like fungus, bacterial, and parasitic infections using the right medication.

But you can deal with molly diseases caused by trauma or injuries as they’re physical problems.

Molly Symptoms You Can Treat Yourself

For the following symptoms, it is possible to treat your fish at home without getting help from the Vet:

  • Gasping
  • Bloating tummy and red marks appear on the fins and body.
  • White specks develop on mollies’ fin skin.

It is alright to treat your fish using Epsom salt. Put one tablespoon of this salt for every five gallons of water, then leave your mollies bath for about ten minutes daily until they are better.

Using Maracyn is also recommended to treat the issue of bacterial infection.

When Should You Need  To Get Help From A Vet?

Take your mollies to a trusted veterinarian if you notice one or a combination of the following signs:

  • Fins clamped.
  • Loss of appetite.
  • Lethargic behavior.
  • Changes in size and color of scales.
  • Have ulcers on the body.
  • Pop-eye or cloudy eyes.


What Is the Ideal Water Temperature for Mollies?

We recommend keeping mollies in an environment between 72 and 78 degrees F.

Avoid using an aquarium heater since it will cause your mollies to become too warm or die!

How Long Do Mollies Live?

Molly fish don’t live long. These animals can live for about two to five years. Their lifespan will depend on the care they receive in your aquarium.

How to Tell if My Molly Is Pregnant?

Here are some signs that your molly might be pregnant:

  • Aloof and aggressive behavior.
  • Rounded and swollen appearance.
  • Increased appetite.
  • Strong bulge below its gills.
  • Prominent and visible gravid spot.

How to Feed My Molly Fish?

Molly fish are omnivorous, so they consume both meat and plants.

But they have developed a strong appetite for plant matter in captivity, meaning they love vegetables over meats.

How To Clean My Molly’s Aquarium?

There are various ways to clean your molly’s aquarium.

But you should vacuum the gravel, change the water, siphon the substrate, clean uneaten food, and waste in your aquarium, etc.


You have reached the bottom of our article. Hopefully, you found the answers you were looking for.

A healthy molly fish will demonstrate these signs: Active swimming, alertness,  rich coloration, bright eyes, and clean vents without stringy feces.

If your mollies fish have unusual symptoms that are the opposite of the signs above, it is essential to identify the cause and treat them as soon as possible.

Thanks for reading!