Cold water fish like Goldfish, Orfe, Rudd and some species of catfish. I have left out Koi Carp on purpose because although they are coldwater fish they are also specifically for keeping in large ponds.
Tropical fish.
Typically heaters are needed for tropical fish tanks. However, if you could guarantee the room temperature where the tank is located will be maintained at the needed temperature for your fish, then you don't need a heater. Most tropical tanks need to be maintained at temperatures of 72 to 80 degrees Fahrenheit, depending on the types of fish in the tank.
Blood parrots are tropical fish, yes they do need heaters.
No. Depending upon the climate you live in, tropical fish may need heaters if you live in a cool place and if you live in a warm place cold water fish may need coolers. Each species has its own requirements.
its for tropical fish and salt water fish. they need to have warm water to survive cause were they live is really warm waters
No
Betta fish do not enjoy currents that come from filters. You could put in a filter but I would recommend not to. Also, Heaters are unnecessary as long as you keep the water 70-80 degrees.
guppies
You need to specify who 'they' are.
no some dont need air like fish dont they need water
i dont think so
Yes but star fish are asexual so they dont need a partner