crackatoa

Is this a standard necessity with angelfish? I read that lower temperatures keep them living longer, but lower their immunity. Now that it's winter, I don't keep my house at 75-79 deg.
I got my first angel back in July, I just got a second one today.
Yes, it's sad that I'm finally thinking of this now. :

kerryve

When your water temp is lower, with any fish that makes them susceptible to ich - its a cooler water parasite. but its also not necessary to keep your water at 30 Celsius all the time. its recommended that they be kept in water temps of 25 to 27 degrees Celsius.

Isabella

Kerryve is right. Any tropical fish is more susceptible to diseases at lower temperatures. I keep my angelfish at 78 - 79 F (I have a heater). I think a heater is necessary for an angelfish (and any other tropical fish) tank. If you get a heater with a thermostat (a lot of aquarium heaters have in-built thermostats), it will heat up your tank only when the tank temp. goes below 78 F for example (or whatever the temp. you set it to be). It will prevent sudden temp. drops, which may otherwise be very dangerous to fish.