Normal rate of attrition?

[FishieMomma]

I have a 55 gal. Partially planted tank with 2 grouchy breeding angelfish, 8 neon tetras (full-size), and 3 full-size albino Cories. Friday I made my usual 50% twice weekly water change and went to the LFS for more cories. I brought home 6 healthy, happy, active Julii Cory catfish. I acclimated them over 30 min. by floating the bag and dripping tank water in. Since then, I have found one dead on the filter intake tube, one stuck between the side of the tank and a decoration, and two dead for no apparent reason. I am now doing another massive water change. The water parameters of the water I am in the process of taking out is:

Ammo-.25 Nitrite-0 Nitrate-5.0. Is is attrition rate normal?


ETA: water temp consistent at 80°

 

[shellieca]

I have a 55 gal. Partially planted tank with 2 grouchy breeding angelfish, 8 neon tetras (full-size), and 3 full-size albino Cories. Friday I made my usual 50% twice weekly water change and went to the LFS for more cories. I brought home 6 healthy, happy, active Julii Cory catfish. I acclimated them over 30 min. by floating the bag and dripping tank water in. Since then, I have found one dead on the filter intake tube, one stuck between the side of the tank and a decoration, and two dead for no apparent reason. I am now doing another massive water change. The water parameters of the water I am in the process of taking out is:

Ammo-.25 Nitrite-0 Nitrate-5.0. Is is attrition rate normal?

ETA: water temp consistent at 80°

First sorry about the losses. I would acclimate them longer than 30 min., I go a minimum of an hour but usually 2-3 & it is possible they weren't well when purchased. It's hard to say what happened but if your Angelskk are grouchy they may not have liked new tank mates.

 

[FishieMomma]

Thanks for the reply. I am down to one of the new Cories left. It looks like the older Cories have some tail rot so I'm going to start Melifix treatment today after yet another water change. I understand I can't do too many when fish are sick.

Perhaps the bacteria that caused the fin rot made the new Cories sick?