# Aquarium fish and temperature.



## sthomas048 (Dec 27, 2007)

Hello all, 

I was wondering does the temperature of the tank water affect fish behaviour ? For example every fish has lower and upper limits in temperature based on its location and natural habitat. Curious if anyone has spent time observing any differences in behaviour/experiences related to temperature. Like if higher temps encourage more boisterious behaviour etc;

Cheers.

Stephen


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## chapman76 (Jun 30, 2004)

Yes, higher temps typically make them more aggressive (if it's in their nature) and lower temps tend to keep them less active.


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## PsYcHoTiC_MaDmAn (Dec 26, 2005)

chapman76 said:


> Yes, higher temps typically make them more aggressive (if it's in their nature) and lower temps tend to keep them less active.


I want to clarify something

the warmer temperatures do not make them more aggressive. 
say a fish naturally comes from an area that is a stable 25-26c. and then the temperature is bumped to 30c, then there will be no increase in aggression, however tis metabolism will have sped up,

now reduce the temperature to 20c, and suddenly its metabolism has slowed, and while its still as "aggressive" as it was before, the slower metabolism means its slower to react and move so it would seem less aggressive as it basically doesn't have the energy to expend on chasing/attacking other fish.

another thing to consider is that change in temperature can be the trigger for breeding, which would most definitely make them more aggressive as they defend their fry.

another thing to consider, with the lowering temperatures slowing the metabolism, they will also have lower immune systems, so making them more likely to succumb to diseases. (for instance I forgot to plug a heater back in after maintenance, and the tank went from 28c to 18c over several days, when I noticed I plugged it back in, however they then developed whitespot. this is something I attribute entirely to the change in temperature(


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## sthomas048 (Dec 27, 2007)

thank you both. PsYcHoTiC_MaDmAn - very interesting stuff. fish science and biology. thats very useful for all fishkeepers to know really.


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## Bachachi (Sep 8, 2004)

As stated by PsYoHoTiC the increased temperature triggers breeding, but also affects their 
eating behavior. As their metabolism increases they become more ravenous, and the 
competition for food causes more aggression.


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