I get asked about it a lot by people I know, and now I wonder too... Could you use a heater meant for bigger tanks in smaller tanks? I mean I have a 250 watt heater (meant for 90 gallons and up) but biggest tank is 29 gallons - but I won't use it because I'm not even sure it'd work - might just fry my fish ><
So on the behalf of myself and people I know in my area, how important is it to use a heater made for a particular size of tank? And why?
(mine is an adjustable heater, 250 watt Ebo-Jäger now made by Eheim, for saltwater and freshwater fish. So useless to me until I get a bigger tank xD)