will comment more later, but to clarify their classification according to thermal preference, bowfin are warmwater fish. the confusion here is what people in the hobby classify based on thermal preference, and what fish ecologists classify based on thermal preferences.
in the hobby, bowfin are temperate fishes, whereas most of the fishes people keep in the hobby are tropical. sometimes people call them coldwater fish (in the hobby) but this is not correct, only relative to their tropical fishes.
in fish ecology, bowfin are warmwater fish, trout and salmon are examples of coldwater fishes, and there is an ambiguous category of "coolwater" fishes where several groups seem to bounce in and out of.
also note that bowfin have a wide range of temperature tolerance...they are found from Canada down to Florida, so they can handle extremes like many primitive fishes. the important thing is to be consistent with temps in captivity, or allow for long acclimation periods. bowfin can live with your tropical fish, but don't expect your tropical fishes to live at all the temps of your bowfin...a warmwater (fish ecology) OR temperate (hobby) fish.--
--solomon
PS-- if you are getting them at 3" you should get at least a dozen...you'll kill off about 10 and hopefully the remainders will make it to that 7-8" "safe zone". bowfin are extremely delicate when young and very prone to idiopathic death.