# What temperature changes can a betta tolerate?



## mathkid (Sep 15, 2011)

I've heard that bettas are sensitive to temperature changes - within "a few degrees" - but what does that mean? In a large tank, the water can vary by a couple degrees in different corners that's OK, yes?

For example - suppose your betta is in 79* water and a disaster happens and you need to net him into new water immediately. If it's 77* will that shock him? 75*? 73*?

Does it make a difference if the new water is warmer or colder? Starting from 79*, is 82* handled better/worse than 76*?

Or, if you're doing partial water changes, if he's in 79* water and you put in 81* water gradually over 20 minutes... no problem?

What about a more typical situation: he's in 79* water and you put in room temperature 71* water - so at the end of the 20 minutes his water has gone from 79* -> 75*?

What about day-night temperature swings, or small-heater temperature swings?


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## Sena Hansler (Aug 24, 2011)

Heaters are designed to slowly increase the temperature, and i've never had a problem with a betta going from say... 63 (it happened recently! scarily...) to 75. but, that is over time. it also depends on the betta... i have some who are drama-mamas when it comes to temperature changes. Some cannot handle a mere 2-4 degree difference, while others can have shocking changes no problem. however, it is never good to make them go through large temperature changes.

for instance, if my betta was in...75 degree water i would never put him into 81 degree water during a water change. Even if he does not show any problems, it can stress him, and can cause them to become ill or susceptible to disease.

i try keeping the water between 77 and 81. take for instance summer here for me last year... my bettas sat at 86-90 for day, NO lights on (otherwise they would have been at 95 at least), and went to 78 for night. None had a problem... sometimes you have to work with what you have, how to deal with it, etc. 

Gives bettas credit...they are hardy  just you want them to live stress and illness free... If you get hot summers, try saving money for tank fans. winter, make sure you have a reliable heater, preferably adjustable.

i had one emergency, with Spartan. Something was poisoning the water...maybe the heater... i grabbed a small bowl I use for water changes, tap water, bit of water conditioner, and netted him. the water difference for temperature was about 5-7 degrees.... But it saved him, as I did not have much time to remove him.


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## callistra (Jun 29, 2010)

General rule of thumb, 2 degrees or less is usually okay. Any more and you have issues. Constant swings, especially dips in the thermostat over night I have always seen result in sick fish.

When you're changing water try to keep it the same temp as the tank. With practice you can make the tap water the same as what's in the tank. If you're aging water then heating up beforehand can be done several different ways.


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