I have always just run a single 250w heater in my 55 gallon & single 100w heaters in my smaller tanks, never had any problems.
Generally they (the fish) should easily be able to acclimate to any slight/gradual temperature changes so long as it isn't really drastic.
Your biggest concern with tropical fish will be during water exchanges and stuff, that's where a digital thermometer comes in real handy to help match up your tap water's temp to your tank temp.
Generally they (the fish) should easily be able to acclimate to any slight/gradual temperature changes so long as it isn't really drastic.
Your biggest concern with tropical fish will be during water exchanges and stuff, that's where a digital thermometer comes in real handy to help match up your tap water's temp to your tank temp.