Molly Fish cold water question

[Rollxr]

Hello, so apprtenly for 5-6 hours my tank’s heater was left unplugged 2 days ago and it dropped significantly from 78-76 degrees to 68-69 degrees. , after that when the tank temp had dropped my molly fish’s back got hunched, will it get better? Does my fish have permanent damage from that temperature drop?! The temperature is better now however (78)i plugged it back in. . and as so far goes for the parameters i am still fixing the pH.

 

[Colin_T]

The fish has clamped fins too and that can be associated with the cooler water or poor water quality. Assuming the water is good (no ammonia, nitrite or nitrate) and the pH and GH are correct for the species, then the issue is probably the cooler water and when it warms back up the fish should be fine.

 

[10 Tanks]

Hello Rollxr. Mollies are the most challenging of the livebearers to keep healthy. They're very particular about their water conditions. The temperature drop was gradual, so that's a good thing. All you can do is wait and continue your normal tank maintenance schedule. These fish demand next to perfect water conditions. So, if you haven't been doing this already, gradually work up to the point you're removing and replacing at least half the tank water every week.

10 Tanks (Now 11)

 

[emeraldking]

Hello, so apprtenly for 5-6 hours my tank’s heater was left unplugged 2 days ago and it dropped significantly from 78-76 degrees to 68-69 degrees. , after that when the tank temp had dropped my molly fish’s back got hunched, will it get better?

Mollies can kept at those lower rates of 68-69 °F but they have to adapt to it gradually. I'm keeping my mollies also at lower rates. They do all fine. But a fast significant temperature drop is something they've got problems with. This could explain the clamped fins and that they look a bit bend. In this case, getting them back to the old temperature would be best thing to do. When a fish is a bit bend by a temperature drop, it's mostly a muscle issue which will become normal again once the temperature becomes higher again.

Mollies are the most challenging of the livebearers to keep healthy.

Incorrect. But yes, only if you look at the common livebearers. But they are for sure not the most challenging livebearers there are. I can name a lot of livebearer species which are far from easy to maintain and to breed.

 

[10 Tanks]

Hello emerald. Yes. I was referring to Livebearers in general. This species is recommended for beginners, but they are very sensitive to changes in their water, like temperature. Actually, they do best in brackish water, which many beginners have no clue about this type of water. The species also has some fairly specific diet requirements if they're to be kept healthy. Platies and Guppies are a much better choice.

10 Tank (Now 11)

 

[Rollxr]

Hello emerald. Yes. I was referring to Livebearers in general. This species is recommended for beginners, but they are very sensitive to changes in their water, like temperature. Actually, they do best in brackish water, which many beginners have no clue about this type of water. The species also has some fairly specific diet requirements if they're to be kept healthy. Platies and Guppies are a much better choice.

10 Tank (Now 11)

I did ask my pet store, where i got my molly fish from. They said that they keep the mollies in freshwater and they are raised in fw. thats why I didn’t make it brackish

 

[speakerman3]

The lower temperature was not extreme for mollies, and that alone should not cause any long-term damage. One thing to consider is that more oxygen is available at lower temperatures, so when you raise the heat up again, it is very important to have pristine water conditions and good aeration. Making the change gradually is also beneficial.

 

[Byron]

I did ask my pet store, where i got my molly fish from. They said that they keep the mollies in freshwater and they are raised in fw. thats why I didn’t make it brackish

You are correct. Mollies are freshwater fish, but having said that...
The natural range is Mexico, Central America, to Venezuela and Colombia in northern South America; isolated populations on several Caribbean islands. Occurs in fresh and brackish water shallow streams, ponds and estuaries in coastal areas. Introduced into Montana, Nevada, California and possibly Florida [US Geological Survey].

But mollies acquired in any pet store will almost certainly be commercially raised and in freshwater only (SE Asia example). The advice from the pet store was in this case bang on.

 

[Naughts]

i am still fixing the pH.

What do you mean by this? Changing parameters can shock and even kill fish.
Mollies do need significantly harder water than most freshwater species, which usually means a basic pH. What are your water's GH, pH and KH?

 

[emeraldking]

They said that they keep the mollies in freshwater and they are raised in fw.

Most captive bred mollies meant for the commercial market are freshwater bred mollies. I do have to mention that there are a lot of Asian fish farmers who do add a serious amount of salt in the water. Not to make it specifically brackish but to avoid any deseases. They do it with more livebearers like e.g. guppies. But I've mentioned a lot of Asian fish farmers, so not all.

In nature they occur in both freshwater and brackish water. But you should not always compare breeding forms to wild forms when it comes to their water type.