Andy Sager
Aquarium Advice Addict
Okay, it sounds like the fish were just too small and it may have nothing to do with you or your tank. These dime size Angelfish haven't gone through the natural die off phase and I would suggest you NEVER buy an angelfish less than a nickle body size.
That being said, it sounds like your 2 Angels have buddied up and if the Koi is not part of the "school", it's best you just keep the 2 Angels and not try to add more. As I said earlier, a 29 gal tank does not have a lot of bottom space to house many Angelfish especially if they are of different sizes.
As for the missing Koi, look outside the tank if you can't find it inside. Remarkably, I found one of my large Angels on the floor and there was barely any opening in the tank top yet it still managed to get out. If you do find it outside the tank, this is more of a sign that it's time for NO MORE ANGELS in their tank.
That being said, it sounds like your 2 Angels have buddied up and if the Koi is not part of the "school", it's best you just keep the 2 Angels and not try to add more. As I said earlier, a 29 gal tank does not have a lot of bottom space to house many Angelfish especially if they are of different sizes.
As for the missing Koi, look outside the tank if you can't find it inside. Remarkably, I found one of my large Angels on the floor and there was barely any opening in the tank top yet it still managed to get out. If you do find it outside the tank, this is more of a sign that it's time for NO MORE ANGELS in their tank.