What Other Fish Will Do Well With Mollies?

[mandy82]

As soon as my tank is doing better and I'm able to add more fish (also after I find a new home for my baby mollies), I would like to add more fish. I would love to have some fancy guppies, but I'm unsure if they are able to live with mollies. What do you suggest?

 

[IovaykInD]

Livebearers usually go well with other livebearers. Just watch their behavior and if anything is abnormal, figure out the problem.

 

[Annastasia]

What size tank are we talking here? And how many Mollies do you have, and what kind are they? Guppies will work okay with Mollies, as long as your Mollies aren't overly aggressive and you have the male to female ratio right. A biggish tank very decorated also helps.

 

[mandy82]

I have two silver mollies and three marbled mollies. My babies are all marbled. It's a 40 gal tank. Since 3 of my female mollies have died since I started the aquarium, my ratio is out of wack. As soon as my babies are big enough, I do plan to find a new home for some of the males so that there will be a better ratio.

If I had a tank strickly for males with no females, would they harm each other?

 

[Annastasia]

Okay, so just regular ones not Sailfins?

I'd first get the ratio right if you want to have any success with the Guppies, as otherwise the male Mollies will probably pick on them. They'll see them as a threat to the females, even though they are a different species. Mollies and Guppies actually can breed together, but this is very very rare, and the fry hardly ever live.

As for an all male tank, do you mean all male Mollies AND Guppies? I think that'd be a bit risky, because of size difference. All male Guppies or all male Mollies could work though, as long as the tank is planted and decorated so they can get away from each other and each have their little territory. It usually works best to have at least 5 to spread out aggression.

 

[mandy82]

Yep, regular mollies not sailfin. Are there any kind of non-livebearers that would work with mollies?

 

[Annastasia]

Oh, sure. You have lots of options. Tetras, Rasboras, Catfish, Gouramis, etc. Any idea what kind of fish you might like?

 

[mandy82]

I like about any kind of fish. I would like to have a variety of fish.

 

[Annastasia]

I can't really give you a list of fish, because there are waaaay too many. So you need to have some idea of what you want...schooling fish like Tetras, Rasboras, Platies...look around, get a list of what you like. Then if you bring it back, I'm sure people can help you with compatibility and stocking.

It's usually best to get fish that will match your water stats though, so you don't have to go changing a lot around. Do you know your hardness and alkalinity?

 

[nmonks]

Hi there --

It's critical to appreciate one thing: most mollies prefer hard, alkaline water. Some do best in brackish water (black mollies, wild-type sailfin mollies). When kept in soft, acidic water mollies tend to develop things like mouth fungus and finrot.

Now, the majority of tropical freshwater fish prefer soft, acidic water. Stuff like neons, cardinals, rams, rasboras, dwarf gouramis, and so on tend to do badly (i.e., they die) when kept in hard, alkaline water. OK, lots of people keep them in hard water tanks, but ask around and you'll hear lots of those people tell you that their dwarf gourami died from bacterial ulcers after a few months, and the neons popped off one at a time every week or so.

So what you want to do is choose stuff that will do well in hard, alkaline water, and preferably species that will not mind if you need to add a little salt. Livebearers are a good call generally, but you can also add things like rainbowfish, kribensis, halfbeaks, glassfish, gobies, and (some) killifish. Keep mollies in a slightly brackish tank, and you can look at things like flatfish, orange chromides, more gobies and killifish, and pipefish.

One nice thing about a hard water aquarium is that they are terrifically stable: things like pH changes and oxygen crashes just don't seem to happen. As aquarists, we often complain about hard water, but the fact is that in many ways there are easier to maintain than tanks with soft, acid water. There are also a lot of plants -- like hornwort and Vallisneria -- that just seem to do better in hard, alkaline water.

Cheers,

Neale

 

[mandy82]

Hardness is 75 GH. Alkalinity 0 KH. pH 7.2.

I do like Dwarf Gouramis and Tetras. As far as other fish, I would have to look them up. I'm new to the fish world so I have to look up pictures to see if I like them.

 

[jonneysprincess]

oooh yes orange chromides are gorgeuos i have 2 they look really nice in a planted tank cos i think it shows off their colour. i hav them with mollies they get on great they like to rip some plants to bits though, but not all

 

[Fish_n_Frys]

I have mollies,

I have:
Guppies
Tetras
Platys

Any type of these would be fine ...

 

[nmonks]

At pH 7.2, which is slightly alkaline, and 75 mg carbonate per litre, which is moderately hard, your water conditions are perfect for livebearers, rainbowfish, and many cichlids. Some tetras will do fine at this pH / hardness level. These include the x-ray tetra Pristella maxillaris, diamond tetra Moenkhausia pittieri, and the ever-popular blind cave tetra.

However, many of them, like neons and cardinals, will be a gamble. Very many people who keep neons and other South American tetras in water with a pH above 7.0 experience the mysterious neon tetra die-off, where fish die for no obvious reason. Supposedly, the hardness in the water inteferes with their kidneys, but really no-one has any idea what the problem is. Other fish that don't do well in anything other than soft, acid water include harlequin rasboras, glowlight tetras, dwarf barbs, Otocinclus, and rams.

There's an excellent but difficult to read book called "The Optimum Aquarium" that describes a huge (I mean, thousands of gallons) aquarium set up at pH 7.0 with a moderate hardness. The authors created this tank to prove that at neutral water conditions you can keep both hard and soft water fish: so they include a mix of fish that would otherwise be incompatible... cardinals, figure-8 puffers, black mollies, and Otocinclus. So it can be done... but it isn't easy, and you will perhaps need to reduce the pH slightly with a bit of peat.

Problem is, the mollies might not appreciate this. Because mollies are hopelessly hybridised, it's impossible to tell by looking which ones need brackish water and which ones do not. The safest option is to keep them all in hard, alkaline (pH 7.5+) water, with a bit of salt if possible. Most (probably all) black mollies can be adapted to marine conditions, where they really prosper. This should set the alarm bells ringing that such fish aren't an ideal choice for a soft to neutral freshwater aquarium. So while you can go ahead and try it out, don't be at all surprised if after a few months your mollies have white patches of slime on the body and fungus on the fins. I've seen this so many times it gets boring to repeat the warning. In hard, alkaline water mollies are tough as old boots, but in soft or neutral water, they are finicky and delicate.

In short, I wouldn't keep mollies with tetras or Corydoras or any other salt-intolerant fish just in case I needed to add some salt. If you keep them with guppies, rainbows, chromides, and so on, adding a little salt will do the tankmates no harm at all, and you could add a bit of coral sand to the aquarium to raise the pH and hardness a bit as well.

Newcomers to the hobby don't really appreciate that "freshwater fish" actually come from as varied a range of habitats as "land animals". It's also a shame the tropical fish stores promote the totally erroneous impression that all "community fish" can be kept in the same community.

Cheers,

Neale

 

[blackguppy]

I agree with nmonks, that Mollies are a brackish water fish. I've found that most other species don't do as well in the salinity that Mollies need to thrive. I'd stick with the guppies and Mollies alone.