temp question

So my temp during the day is about 76. (the lights are of at night) When I wake up in the morning my temp is around 71, but in a short bit it goes back up to 76.

I don't own a heater - is this 5 degree difference hurting anything?

plant growth? fish?

(by the way, my fish seem to be living fine, i have had most of these fish for 2 years or so.)

Thoughts

[lescarpentier]

Those 5 degree temperature fluctuations are definitely harmful to the health of your fish,(not sure about the plants).I would immediately invest in a heater.If you don't want to look at it in your tank you can buy a Hydor inline heater,which will maintain your water temperature within a degree or so.There is a 200 watt version that will fit the 1/2 inch return line of your 2215.

Hmm...they have been doing fine with out one for a few years.

Not trying to sound rude, but what is the harm done to the fish?

[lauraleellbp]

Some fish are hardier than others. Some fish actually require fluctuations in water temps to emulate the conditions they experience in their natural environments. Many species of fish need PWCs with cooler water to stimulate their breeding. Corresponds with warmer weather temperatures melting ice and snow and bringing an influx of cool clean water into their streams/lakes/ponds. Many fish in tropical climates time their breeding around the rainy season, when the rains bring in cooler, softer water.