Mollies are great fish. They come in fun and exciting colors and shapes and many of them have great fins. They can be interesting to watch in their tank. However, they are often sold as community tank members and this can lead to problems. Sometimes these fish are rather aggressive and even down right mean to other fish that they share a home with? So, who are the perfect tank mates for the molly?

General Information.
The first thing that you should know is that the mollies require a fairly good size tank. You should have at least 20 gallons for them and a taller tank is better than a longer one. Having adequate space will make your fish more calm and easier to get along with other fish in the tank. Before you decide what fish to put with your mollies you will need to decide if you are putting salt in your tank. Mollies thrive best in brackish water and can actually handle a wide range of water conditions fro fresh to completely marine. For more information on molly care you should check out the article Mollies: Basic Care. After you have chosen your salinity then you can figure out who you want to keep with them.

General Rules.
As a rule mollies can and will bully other fish if they don't have adequate space and there are certain species of fish that are more likely to be bullied. It is also important to choose tank mates that aren't real territorial (unless they like the bottom) and who won't nip at any fins (especially true if you are buying a fancy finned variety such as the sailfin or lyretail).

You have several options for keeping your mollies in freshwater. Just remember that they aren't always peaceful tank mates.

  • Most other live bearers are poor choices including the guppy and the swordtail. At the same time they do get along with platies without a problem and the two species are often kept together. Platies can also handle a bit of salt so you can add aquarium salt to the mix if you are looking at giving them some salt.
  • Gouramis can make a good choice, but you need to be careful what type you buy. The most peaceful option are honey gouramis and a pair of them can be kept with mollies without issue. Most dwarf gouramis will work, but at the same time you don't really want a pair. A female will get chased a lot and the males will fight. You can add one beautiful gourami to your tank for a great look. Larger gouamis should be avoided.
  • Danios and rasboras often do well with mollies. Most tetras can do well, but it should be noted that they prefer softer waters. Here is best if you know a little about your local water conditions. We have very hard water and so does the location where we buy fish. Because of this the tetras that we have bought are already conditioned to hard water. They are doing well, though they will never breed in the hard water and many would say that they won't thrive. Each of these should be kept in a group of 5 or more so make sure that you have plenty of space for all the fish.
  • Minnows (including white clouds) will also do well. They too should be kept in a group.
  • Rainbow fish come in a huge variety of options and most of them will do well with mollies. Dwarf species may be an even better option, especially if space is an issue.
  • Loaches, plecos, corydoras, and otocinculus catfish are all bottom species that will do just fine with your mollies. Make sure that you look into their specific needs. Many loaches, corydoras, and otocinculus catfish will do best in groups of three or more (of their own species not a mix and match). On the other hand, it should also be noted that most plecos grow very large (as much as 2 feet) and they need a very large tank (usually more than 75 gallons). If you don't have this amount of space there are a couple of dwarf species (rubber lip pleco and the bristlenose pleco), but you need to make sure that the species you are getting will fit in your tank.
  • Mollies have no problem with many invertebrates as well. You can keep them with African dwarf frogs, ghost shrimp, snails, and even other shrimp species. It should be noted that if you are looking at breeding dwarf shrimp the mollies are likely to eat shrimp babies. Cray fish can also be kept with the mollies if there is enough space and if they aren't aggressive and will leave the mollies alone (research the individual species you are planning on getting).

Brackish Water.
Brackish water is a little more difficult than fresh because finding fish is a little harder and finding information about the different species can also be hard.

  • The dragon goby is a very unique brackish water species that is very peaceful (contrary to many beliefs). If well fed the dragon goby won't even eat any live babies! (For more information on the dragon goby check out the article The Dragon Goby. It is recommended that you have at least 29 gallons for the dragon goby and when adding mollies you should consider at least 55.
  • There are a few other gobies that can also do well with mollies. Many of these need large fish tanks, so you will want to do research on the individual species that interest you to make sure that your tank will meet their needs. Knight gobies and bumble bee gobies often do well with mollies.
  • Ceylon puffer fish have also been kept with brackish water mollies with success.
  • Celebes Rainbowfish is another great option.
  • While getting into cichlids one always needs to be careful, but the orange or green chromides cichlids often do well with molies.
  • Glassfish are often dyed and sold as painted glassfish. They thrive in the brackish water and will do very well with your mollies. They do need to be in a pretty good size group.
  • Sharks. There are a few shark catfish that are peaceful and will do wonderful with mollies. Many of these will grow very large and will eventually need a very large tank. However, the white tip shark and the black fin shark are both options for keeping with your mollies. They do best in groups though and will need a huge space.

Marine Conditions.
Mollies can do well in a saltwater tank (either a fish only tank or a reef tank). However, many feel that they take away from the "marine" look and feel of a tank. You have to decide that for yourself and it is true that a few black mollies can look very lovely in your salt water tank. If you are going to add them to a saltwater tank (or are starting them in a saltwater tank) then it is a good idea to look for peaceful fish that won't attack the mollies. Here are a few, but there are likely many more!

  • Damsel fish. Most damsels are pretty aggressive and you want to avoid the types that are likely to attack your mollies. However, blue damsels and yellow tailed damsels are often relaxed enough to keep with mollies.
  • Clown fish are good for your mollies as well.
  • Blennies and gobies pretty much ignore the mollies and visa versa. This can be the perfect situation for your mollies.

While these are great options for making your tank you also need to make sure that you are doing the research on the individual fish that you are bringing home. It is a bad idea to bring home a fish and then find out that it is going to get much larger than you had anticipated or that it eats different foods. Therefore plan things out carefully.

Mollies can make great members of a community tank. However, if problems do arise remove the problem molly (usually just one) and place it in a dish. Then you should move around the decorations. Give your other fish awhile to settle in and then add the problem molly back in. He or she will feel like they are in a new place and will be less dominant. Now you have all that you need to keep your mollies in a great tank!