Cold water water changes

[Fishy-Botany]

So my apartment's hot water heater broke and the landlady is taking forever to replace it. so far a week. It's time for water changes and im worried the 60f water will stress out my fish. The temeperature my fish are at is 80f.
In your experience would a 20% water change do more harm than good?

 

[philipraposo1982]

I am not going to pretend to know how much of a dip in temperature is going to affect the fish.

But I would only want my tank to drop a 2-3 degree max in a short time like a water change. So if it's possible maybe drain the tank and have the water fill at a slow slow pace to allow the heater to help out.

Is this possible for you?

 

[Drstrangelove]

A 20% change with 60 F water in an 80 F tank will only cause a 4 F drop. Even if the change is instant, it would likely not affect the fish. It won't of course be instant as it will likely happen over the course of 10 minutes.

Not a big deal imo. When a fish swims around in rivers or lakes, it likely experiences changes like that all the time. Saltwater fish probably have less variation of course, so I would make it slower with salt water fish.


https://www.bassresource.com/bass-fishing-forums/topic/92318-temperature-and-depth/

Here's an example that someone gave for a lake. At the surface it's 82 F, but at 45 feet it's 51 F.

Here's another example from Lake Michigan. https://water.usgs.gov/edu/temperature.html

And I would guess that people that do 75-85% water changes, have temperature changes larger than 4 F.

 

[Lepisosteus]

I used to do water changes with cold water. I would do them right until November with cold water so the well water was really cold. Never lost a fish. When the water felt really cold I would do 2 smaller water changes instead of one big one. So one quick one in the morning one quick one in the afternoon. Never noticed a huge difference

 

[Chockful O Phail]

And I would guess that people that do 75-85% water changes, have temperature changes larger than 4 F.

4-5* cooler or the same is what I shoot for during WCs. Sometimes I miss the mark and hit 8* cooler or so. Only time it ever affected the fish was a couple times it was 5*+ warmer. I've lost several fish to that but never a cooler change.

 

[Lepisosteus]

Cooler water is similar to natural effects. Like a large rainfall.

 

[MrsE88]

I don't think you'll have any issues with the temp drop.
If you are really concerned you could fill a bucket and put an aquarium heater in it to bring it up to temp.

 

[Fishy-Botany]

This is easing my stress thanks everyone. Since all my tanks are over 40 gallons I'll add water slowly like philipraposo1982 said. That way the water circulation and heaters catch up to the new water.

 

[mattison187]

I have done straight cold water changes for years. Youll be fine

 

[TheLastKon]

At that temp it's fine. Only time I had fish actually get effected was when I did a 75% wc with rain water that was at 50 degrees...not only that but I did it quickly. Very quickly all the fish acted differently. Some swam like crazy others froze a few went belly up. Luckily no losses...used warm water from another tank to raise the temps and the fish were fine within the hour. Lesson learned.