The Shimmies!

[Meggie :)]

I have no idea what to do with them The only tanks I have are a temporary ten gallon fry tank (which I want to add salt to as well), my ten gallon with the balloon mollies and shrimp, 2 2 gallons, and 2 5.5 gallons. I'm guessing they can't survive in brackish water... I don't know any store that can take them...Man I really messed up, huh?

 

[FishFanatic04]

People keep mollies and cories all the time Meggie. There must be some other solution.

 

[Meggie :)]

I am just really starting to like the idea of brackish if it's better for them

 

[FishFanatic04]

Keep your fry with the mollys and move the cories to the fry tank?

 

[nmonks]

Indeed. The problem is that some of the time it doesn't work, and that's one reason we see so many molly health questions here and elsewhere.

Mollies in slightly brackish water = almost certain to stay healthy.
Mollies in freshwater = seems to be about a 50% chance of them staying healthy unless you keep water quality perfect and understand how to keep water chemistry stable.

Can people keep mollies in freshwater tanks successfully? Yes. Is it the easiest way to keep them? No.

Cheers, Neale

People keep mollies and cories all the time Meggie.

 

[Meggie :)]

Unfortunately, the fry tank is set up in the laundry room, it is EXTREMELY temporary...

 

[cherbusy]

I think it depends on what they were kept in when you got them.

No, that's a myth.

Here's the deal:

In the wild Mollies mostly live in freshwater. Usually not far from the sea, so very much the coastline of North America through to Brazil, but in freshwater nonetheless. They do live in brackish water in some parts of their range though, and occasionally get exposed to fully marine salinities, for example in mangroves.

Aquarium Mollies are not a true species. They are ALL hybrids of one sort or another. Like their ancestors, they can do just fine in freshwater. But generations of aquarists have noticed that Mollies are always easier to keep when a little salt is added. This doesn't mean you can't keep them in freshwater, but rather the probability of disease becomes less when salt is added.

The reasons for this are unclear. There are three possible explanations. The first is that some Mollies have more "brackish water Molly" genes in them than others. I used to believe this, but I'm very skeptical now. The second is that sodium chloride reduces the toxicity of nitrite and nitrate, both of which cause problems for Mollies. Contrast the fact Mollies are sensitive to water quality in freshwater tanks to the fact they were used to cycle marine aquaria where they could be virtually guaranteed to get through any nitrite spike you might have to deal with! Finally, there's the increased carbonate hardness provided by marine salt mix. This buffers the pH, preventing the inevitable pH drops you get between water changes. Again, Mollies seem to be acutely sensitive to low pH, perhaps more so than other livebearers such as Guppies or Platies.

The use of marine aquarium salt mix provides a two-fold benefit: reduces nitrite and nitrate toxicity, and then buffers the pH and reduces problems with osmoregulation. Plain aquarium salt only provides the first benefit, which is why I don't see any point to using it. If you're going to add salt at a meaningful concentration, you may as well use proper marine aquarium salt mix. There are plenty of compatible fish that tolerate SG 1.002, including such things as Australian rainbowfish, horseface loaches, brown hoplo catfish, common plecs and quite a few cichlids. Lots of plants thrive at this salinity too.

Cheers, Neale

 

[cherbusy]

I have had 2 Mollys for several weeks in a fresh water tank, along with 2 platys and a white cloud. All of a sudden both Mollys, but one in particular, became so listless that the platys began to poke at him. It seemed as if he was dying! I was so distraught that I would lose the fish, but had heard and read that the reason Mollys need a bit of salt is that they tend to lose electrolytes. Made sense to me so I purchased some aquarium salt, which is cheap to buy. I had separated the 2 Mollys into a smaller tank by themselves to save them from the poking from the platys. I added a bit of salt and within about 3 days the Molly who appeared to be dying came back to life! Both Mollys seem to need more rest than other fish, and I'm a brand new keeper and just learning. But they're alive and well, and I am thankful I added a bit of salt. I was told in one store that in order to use salt I would need an extra heater as the salt doesn't melt easily, etc. and that I shouldn't bother. That was NOT good advice. I did NOT have to have an extra heater, and I just used the teaspoon of salt in some water, ground it up a bit with a utensil before pouring it into the tank. Worked fine.