fish are not that stupid i would say 45 degree angel about half way up the tank side or back the only reason
you need heater shields is for big fish that throw thing about like rocks and bog wood and heaters and filters
or smash the heater against the tank side
good luck biff
The evidence of this is.....?
Try telling that to the various people that have had fish such as bichirs, plecs and stingrays die from laying on heaters.
as soon as it starts to warm up the fish swims of i have seen fish resting on heaters befor but as soon as they come on the fish is off there not that slow not unless theres something wrong with the fish fish are not stupid