Care Guide for Mollies: Feeding, Breeding and Tank Mates

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Care Guide for Mollies – Feeding, Breeding, and Tank Mates

One of the most popular aquarium fish found at pet stores are mollies because of their wide selection of colors, energetic behavior, and ease of breeding. If you are looking for a livebearer (or fish that bears live young) that is bigger than a platy but smaller than a swordfish, then mollies strike a happy medium. While molly fish are fairly easy to care for, beginners sometimes struggle with them, so find out the secret to caring for mollies and successfully breeding them in your home.


What are Molly Fishes?

The prolific livebearer can be found in saltwater, freshwater, and brackish habitats from the Southern United States to Columbia. They are shorter than platies and can grow to about 4-5 inches (10-13cm). They are surprisingly good at cleaning aquariums, constantly scavenging for leftovers and pulling off hair algae with their flat mouths.

What are the different types of mollies? The most common species in the aquarium trade include Poecilia sphenops (short-fin molly) and Poecilia latipinna (sailfin molly). Hybrids are selectively bred for black, dalmatian or balloon-colored mollies.

Mollies are very popular because they come in a multitude of colors, patterns, and shapes.

Mollies require salt in their water. There are many fancy mollies that have been bred in exotic locations, where salt water is more affordable than fresh water. Fish farms raise fish in brackish water with high pH and high GH (or hardness) to keep them healthy. When these brackish-bred mollies are transported to wholesalers, fish stores, and home aquariums that use fully freshwater setups, the change in water parameters can cause their kidneys to shut down. Your mollies might not experience any problems if they have hard tap water. However, mollies who have soft tap water may be susceptible to diseases such as ich, livebearer disease, and white spot disease. To increase the beneficial minerals of your fish tank, Wonder Shells or Seachem Equrium can be added to people who have soft tap water.

How to Set Up an Aquarium for Mollies

Depending on the type of molly fish, we recommend getting an aquarium that holds at least 20 gallons of water, but a 29- to 55-gallon tank is more suitable for larger species. For most homes, they require an aquarium heater to raise the temperature to 75-80degF (24-27degC). Because of their tolerance for salt, they prefer higher pH, KH, or GH.

How much molly fish should you have? Mollies, like many livebearers love to breed so we recommend at least two or three females for each male. This allows the girls to have a break from their constant attention. (A male can be identified by his stick-shaped anal fin called a gonopodium, whereas a female has a fan-shaped anal fin.)

Female (left) and male (right) sailfin mollies

Are mollies known to nip other fish’s fins In general, mollies can be peaceful fish. Mollies are active fish and can often be seen nibbling on food items to check if they’re edible. They may not like slow-moving, long-finned fish as mates.

What fish can you put with mollies? They do well with other community fish that live in similar environmental conditions and are close in size to avoid predation. We have had great success keeping them with cory cats, danios and tetras as well as barbs, loaches and other livebearers. You should not put larger mollies together with smaller animals such as cherry shrimp, because they are more likely to be eaten.

What do Molly Fish Eat?

Mollies are not picky eaters and are first in line to gobble up anything you drop in the aquarium. Mollies are omnivores and need a variety of protein and vegetable options. You may need to reduce the amount of food you give your mollies if they have a lot of normal-colored poop hanging off their bodies. Also, if you find they are outcompeting other fish for food, consider feeding fish foods that scatter all throughout the tank to give other animals a chance to eat.

Balloon Mollies are bred for a rounder body shape. You should check their waste to determine if they are being overfed.

How to Breed Mollies

Hobbyists joke that all you need to do is add water and livebearers will multiply. Just make sure you have at least one male and one female, and then wait 30 to 60 days for the baby fish to arrive. While a new female might only give birth to a few fry, a veteran mother can have more than 50 offspring. The adult mollies will predate on their own young, so increase their survival rate by providing lots of dense aquarium plants like water sprite, water wisteria, and Pogostemon stellatus ‘octopus’ as hiding spots.

Baby moles may have drab colors when they are born, but will soon develop vivid colors like their parents.

Livebearer fry are much larger than the tiny eggs that hatch. They can eat crushed flakes and small fish food, Repashy gel (in powder form), as well as live baby brine shrimp. Depending on the water temperature and amount of food eaten, it may take four to nine months for a baby molly to reach juvenile size and be ready for rehoming. Learn more about how to sell your extra mollies in our article on How to Breed Aquarium Fish for Profit.