Angelfish dead, no reason found

1 of my angelfish recently died. I have had him about 3 weeks and he seemed to be in good condition when I purchased him. When dead, he showed no signs of disease etc(fins were fine, no white spots). Another angel fish, slightly older is nowhere to be found. I removed the Hornwort in my tank and moved around the driftwood but could still not find him. I am assuming he is also dead. None of the other fish are showing signs of stress or disease. Ammonia and Nitrite are at zero. Narrate is at about 20(my tap water is high to begin with).

 

One dead, one missing, sounds like a potential murderous tankmate. What else is swimming in your tank?

 

4 Cory cats, 3 Gourami, 2 pictus cats, they never bothered the angelfish and the angelfish are to big to fit in their mouths, 2 clown loaches( they need to go in a bigger tank, I should have a couple more)

 

A lot of bullying occurs at night. Pictus cats become active at night and can stress a fish literally to death. It doesn't take long for a group of fish to consume a fallen tankmate.
Pictus do better in larger groups, where they pick on each other rather than other tankmates.

 

So it might have been the pictus cats?

 

Possible. Watch the pictus at night and see if they shadow tank mates swimming in the upper level of the tank. That's typical Pictus behavior. If the tankmate swims away, the pictus becomes more aggressive & follows.