coolwater fishes

i have a single Green Sunfish in a 25 gallon, he is really stunning, and fun to watch, and he has more personality than oscars. i've trained him to jump completely out of the water for worms and other food, and he eats flake as well.

but i still havent found ANYTHING that is compatible with him, he nearly killed (i got it out before it died) a pleco 3 inches larger than it, and it ate a 3 inch swordtale and a 3 inch algae eater (the fastest, hardest to catch fish ive ever had), and he ate crawdads.

i dont have a heater on the tank and i think it stays around 65-70, but he lives in my climate, with water in the 40s-50s in the wild during winter. i saved him from an evaporating puddle.

i would be intersted in selling him for pretty cheap if you want.
 
will blackskirt tetras, zebra danios, & platies be ok in 68 degree water?
 
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