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


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 is a Molly Fish?

The livebearer is prolific in all water habitats, including saltwater and brackish. It can be found from the Southern United States up to Columbia. They have a more streamlined body compared to platies and can reach up to 4-5 inches (10-13 cm) in length. 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 have been selectively bred to create black, dalmatian, lyretail, balloon, gold dust, marble, platinum, creamsicle, and other variations.

Mollies are very well-liked because they come with a variety of colors, patterns and shapes.

Do mollies need salt in their water? Many fancy mollies are bred in overseas locations where salt water is cheaper than fresh drinking water. Therefore, the fish farms often raise them in brackish water that has both high pH and GH (or water hardness). 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. We recommend adding Wonder Shells and Seachem Equilibrium to soft tap water users. This will increase the levels of calcium, magnesium, as well as other beneficial minerals, in the fish tank.

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). They also prefer pH, KH and GH higher because of their tolerance for salt.

How many molly fish should I have? As with many livebearers, mollies love to breed, so we recommend getting at least two to three females for every male. This allows the girls to have a break from their constant attention. A male is identified by his stick-shaped gonopodium (an anal fin), while a female has a fan shaped anal fi.

Male (left) and Male (right) sailfin moles

Do mollies nip the fins of other fish? Generally speaking, mollies are peaceful fish. However, they are very active and often nibble on things to see if they are edible. They may not like slow-moving, long-finned fish as mates.

What fish are you able to put with mollies. They can be kept with other community fish who live in the same environment and are similar in size, in order to avoid predation. We’ve had success keeping ours with cory catfish, danios, tetras, loaches, barbs, 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 does 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. If your mollies have strings of normal-colored poop hanging down from their bodies, it is possible that they are being overfed. You might need to reduce their portions. If they seem to be outcompeting other fish, you might consider feeding them fish foods that are scattered throughout the tank. This will give them a chance for other animals to eat.

Balloon mollies are bred to have a rounder shape, so check the amount of waste they produce to see if you are overfeeding them.

How to Breed Mollies

Hobbyists joke that you only need to add water to make your livebearers multiply. Make sure to have at least one male fish and one female. Then wait between 30-60 days for your baby fish to arrive. A new female might only give rise to a few fry while a veteran mom can raise 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 Mollies might be born with drab colors initially, but they will quickly acquire the vibrant hues of 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.