2 dead rusties! Help

[Jon Ala]

Hey all, in the last 2 weeks I've had 2 small rusties come up dead floating at the bottom. I have 6 yellow labs 1m/5f and what I believed to initially be 6 rusties 1m/5f but my theory is that the large dominant rusty may have killed 2 smaller males? I'm not 100% sure I the 2 dead fish were m or not it's just a guess. My water parameters are perfect and my tank is fully cycled. I also have 3 acei 1m/2f and 2 red top blue zebras 1m/1fm all in a 55 gallon with plenty of filtration. All of you experienced aquarists help me out! Thanks

 

[Elkairos]

Details on the dead fish.. Nipped fins? Scales missing? Strange behavior before dying.

Current live fish behavior? Looks? Tank size?

 

[Jon Ala]

All of the other fish look fine and are more colorful than they ever have been and as far as behavior they seemed fine. Overall aggression in the tank is really low and spread out. I tried to do an autopsy and only notice what looked like to be bruising? No signs of disease or anything.