fresh water sting ray there are alot of easy discus. as long as you have right temps and clean water discus is not hard any more. with that said wild discus and angels are still hard to care for cause they are wild and not tank rased
Rarely or never bred species always garners my respect. Deciding to try something all others have failed at takes a certain die hard commitment. Another thing I respect are those that maintain endangered or exctinct species in the wild. Most are not exactly pretty, nor the nicest fish. They do it for the future generations so that the species might one day see itself back in its original habitat. I think I will always have a soft spot for Goodeids because of that.
"In the land of the blind, the one-eyed man is king" Desiderius Erasmus
I would say wild discus. As per your thread title...The pinnacle of freshwater fish keeping for me would be breeding the more difficult species. I'm trying to get a few more jaguar cats so I can attempt to breed them. It's never been done before, and that would be my biggest goal. Dedicating a 220g to a group of 6 in the near future. That is my holy grail as of late.
125g semi planted. 2 silver angels, 14 silver tips, 16 white fin ornatus tetras, pair of Nicaraguense, pair of nototus severums, trio of firemouth cichlids. 2 FX5s, 1 1500gph circ pump, 2 48" LED lighs, and a HUGE piece of driftwood.
For me, fish like gar or paddlefish/sturgeon. Not just the size, but the history of the animal and the odd conditions both may require. With long nose fish to be kept successfully, open spaces and clearly defined walls are important to the health of the fish. You see what happens to illkept needlefish in lfs's everywhere, busted up noses that will never heal to their full glory. The diet of a sturgeon is what makes these beautiful fish hard to keep. Not to mention they are adorable little monsters.