If you live
where the temperature is always 24oC or 75oF, ±2oC
or F, then you will not need a heater.
Remember the fish are "tropical" fish and need tropical
conditions. The temperature of the tank needs to be between 24oC and 28oC (75oF
and 82oF) at all times. You can get second hand heaters or cheap unbranded ones,
but to save yourself a lot of trouble, spend the cash
on a reliable one. Make
sure the glass is tough and all the joins are properly sealed. The problem with
the cheaper heaters is that if a problem occurs, the glass can crack or the joints
are not secure; you can end up with
electrocuted fish and possibly electrocute yourself. Most heaters have a
thermostat to regulate the water temperature. Adjustments are made easily, which
can be handy when trying to fight off disease or induce breeding. Ask your aquarium
dealer for advise. Stick a thermometer to the side of the tank; it lets you keep
an eye on the temperature of the tank at all times.