sunfish do need a bit cooler water(around 70) or they wont live for very long,i know ive had plenty and have one as of right now actually,they are pretty agressive and love to eat feeders,you'd be surprised how much they like em haha,when I feed mine as soon as I open the lid he waits for me,if you'd like Ill get a pic,also with the sunfish they will only take a few days to get adjusted to the tank,although your tank is pretty small for that many.