Dead Pictus Cats

[Chaydell]

Long story short I came home from work to find 2 of my 3 pictus cats dead. Did a water test and everything was good. Ammonia 0 nitrite 0 nitrate 20 ppm.

None of them were acting sick or weird and the one that's left is still acting normal. I am assuming they were killed by another fish but were both were partially eaten by the time I got home so it is hard to tell. I have a rainbow shark, flying fox, a pair of Bolivian rams and 12 tiger barbs in the tank. I'm considering getting the pictus cats back to 3 but want to try and avoid another killing.

So any ideas on what might have happened? I have what I thought was plenty of hiding spots for the cats but after this I think I am going to add more. I'm also now concerned that my tank may not be big enough even tho past research led me to believe it was. The tank is 55g 4 ft long. So any thought on what happened and how to avoid it or if I should just stick to one pictus for now.

 

[Ninjouzata]

How big is your rainbow shark now? That'd be the first one I'd look at.

 

[Ryan10]

Have you treated the water with anything new or used any meds recently?

 

[Chaydell]

So the rainbow shark is about 4 inches long, same as the pictus cats.  No meds and nothing different to treat the water.  I'm thinking it is the rainbow too and am wondering if I add some more cave and hiding spots if I can avoid this happening again.

 

[bricko]

My pictus was hard as nails so i doubt it is disease related.  Probably the rainbow shark.... 

 

[Chaydell]

Ok so it seems like the rainbow is likely the culprit.  Is it reasonable to believe that adding some more caves/hiding places can make for a safer environment?
 
I'm not willing to lose the rainbow, despite the fact he can be a pain in the rear, so if adding more hiding places doesn't have a chance of making the environment safer for pictus cats I'll need to rehome the lone survivor.