Gary, that reminds me of a Chiclid we got from Lake Malawi in Africa. We got it from an independent pet store probably about 19-20 years ago. It was a beautiful Orange in color fish with florescent tones throughout and a bright yellow/orange dorsal fin and some of the most beautiful egg spots on the anal fin. The color of the egg spots would change depending on whether or not this fish was happy. When we got the fish, it was only about 1" long and I chose that fish specifically because of the florescent tones.
Well, time flew by and I had a very established tank (many years past the current establishment of yours). I am in no way disrespecting your tank (it's coming along nicely and it looks great!) but to let you place things in perspective, my back wall was nothing but solid and thick algae, which made the tank basically self sustained, even with food for the fish.
One year we had some babies. I couldn't tell who the parents were but I counted 13 babies. They were so small and there were SO many hiding places amidst the rocks and plants that there *could* have been many more. Anyhoo, I "officially" counted 13 with this particular batch. One of these babies started coming out of the rocks about 2 months later and it was the most beautiful Cichlid I had ever laid my eyes upon. Words could not even describe just how beautiful this fish was....and it was not your "typical" Cichlid colors. It was multi-colored with so much florescence that it looked like it was a saltwater fish and not a freshwater fish. At this time, I had Tetras and Cichlids all in that same tank, since they both come from the same lake in Africa.
Over the next couple of weeks, I notice the Tetras disappearing and some of the babies were never to be seen again. So, I bump up the feeding schedule. That one Orange fish I loved so much had now taken a turn. I caught him chasing the other fish around and witnessed him eating two of them. Now at this point, I wasn't worried about the multi-colored fish, which I considered my "prized" Cichlid. It was still considerably smaller than the Orange fish, which at this point was close to about 4" long, making the multi-colored fish able to get into safety areas that the Orange fish could not fit into.
Fast forward about 6 months. All of the Tetras are long gone. I come home and my prized fish's skeletal remains are floating at the bottom of the tank.
I didn't fry the Orange fish but lucky for him my neighbor stopped by at the exact moment I had the Orange fish in a bucket, ready to dump in the toilet. She ended up taking the fish (she didn't want it to die) and placing it in a smaller tank all by itself. That damned fish lived another 5 or 6 years before I was told the great news that it had passed on. I'm not one for vengeance but in this case, even after 5 or 6 years had passed, I threw a party on its passing into fish heaven.
I know it's stupid and I know it's just normal nature but I had to draw the line with that Orange fish at some point, much like you did with your Australian Yabby.
Tom