Dalmatian Molly strange behavior

[Jazzfish]

So for a few months, off and on, my Dalmatian Molly would hang out at the bottom of the tank just flapping her fins and tails as if she was swimming. She would just chill at the bottom for hours. And just today she started swimming around with the back of her body to the left more. She only is swimming like this. She doesn’t wave her tail around normal anymore. What’s wrong? What should I do? I did some reading of other discussions and I’ve concluded it’s the shimmies for the first of her symptoms but I’m worried and can’t find any information about the strange swimming she is doing.

 

[Byron]

This is most likely a reaction to problems with the water. What is the GH (general hardness), pH and temperature?

 

[Jazzfish]

I don’t know, I just saw tonight that knowing that stuff was important. I plan on getting a kit soon to check the PH and make sure it’s either neutral or somewhat acidic. Have you ever heard of a Molly swimming with their tail like that?

 

[Circus]

I agree with Byron, it is likely the water is too soft. I believe that when mollies suffer from softer water and act like this it is called "the shimmies".

 

[Byron]

I don’t know, I just saw tonight that knowing that stuff was important. I plan on getting a kit soon to check the PH and make sure it’s either neutral or somewhat acidic. Have you ever heard of a Molly swimming with their tail like that?

You want to know the GH and pH of your source water, whatever it is. You may be able to ascertain this from the water authority, check their website (if you are on municipal water). The temperature obviously you control, so you should be able to post that. But these parameters are critical for fish.

As for shimmies, this is a condition that can be caused by any one of several issues. This is common with fish, which is why diagnosing a problem is so difficult. The parameters (esp GH, pH and temp, KH is of less importance here), water conditions (ammonia, nitrite, nitrate), internal protozoan, pathogens, genetics, injuries...any of these can cause shimmies, clamped fins, lethargy, rapid darting, etc. This is why when a member asks about a peculiar action of a fish, we ask for so much data.