Random Acara Death

[Beetlebug515]

Good evening all. I just found one of my 3 inch electric blue acaras dead in the bottom of the tank. He has been acting perfectly ever since I got him about 3 months ago. Right up until he died he acted normal. He had no missing fins/scales, no ich, no injuries. I tested all of my water parameters this morning (I am a Nazi about water quality) and came up with this:

Ammonia-0
Nitrite-0
Nitrate-15
ph-7.4
dKH-4
temp-80.6f

My tank is a lightly planted 75g. He was in the tank with 2 other EB acaras, 2 green terrors, 2 adult denison barbs, 1 adult Senegal bichir, and one sailfin pleco. The only thing that happened in the tank today was the addition of a paratilapia bleekeri. Even if the fish was carrying anything, I cant think of any disease that would kill a fish that fast. All tankmates get along great , despite the warnings from my LFS when I told them I was going to put green terrors with acaras (patiently waiting for them to breed).

If you guys have any ideas on why my acara would die so suddenly I would love to know. Thanks in advance.

 

[petspoiler]

bleekeri might've chased and harassed it to death, even without wounds. maybe at night. they can be tough on a fish they don't like.

 

[duanes]

I agree with petspoiler, Paratilapia can be quite aggressive in a small tank, and see any other cichlid with iridescent blue color as competition, thus something to be eliminated.
They also tend to be more crepuscular than other cichlids, and can use that as a territorial advantage.
I've had a very alpha Paratilapia seek out and destroy all others in a 500 gal pool.

 

[Beetlebug515]

The bleekeri was in the tank for about 3 hours before I found the dead acara. I had just brought that guy home, and I didn't, and still haven't noticed any sign of aggression from the bleekeri. Do fish have things like strokes and heart attacks?