New Angel fish not eating, HELP?

[ppo8820]

I have a huge hex tank at work (group home for young guys). I bought 1 angel fish who is silver/black striped. Then about 2 weeks later I got 2 koi angel fish, the same size as the silver. They all seemed to get on nicely at first, but then 2 days ago I noticed one hiding out behind the filter intake tube. I added some food to see if I could coax him out but he didnt budge. The other 2 scarfed down the food, as did everything else in the tank.

I tested the water and its perfect. No ammonia, nitrite, and 10ppm of nitrate. I have a tank at home with 1 small black angel fish, so I brought the koi home and introduced him tonight. They immediately started hanging out together and are about the same size. I know sexing them when young is hard, but the koi appears to have the shapes that go with being male, and the small black one has matching traits of a female. The koi isnt hiding anymore and they are swimming around together. Is this a match? Why would he have been hiding in the other tank after 2 weeks of being out and eating well?

Thanks in advance. Im VERY attached to my baby black angel and I do not want her getting hurt or anything, which is why I am paranoid about this introduction. P.S I use the tank at work as my QT and I only buy fish from a local fish only shop that gets their stock from local breeders.


UPDATE: Still not eating today and when I fed the other fish, he looked at the food and started opening his mouth and closing it really fast and was looking all around, but didnt swim to get any food. I know this isnt a good sign, but I dont know what else to do.

 

[ppo8820]

I forgot to mention I moved him to my tank since the silver one was bullying the koi angel into hiding and I had nowhere else to put him where he would be safe. I usually QT all my fish, but this was a situation where I had no alternative.

 

[shark21]

I wouldn't worry to much the Koi will come around. He is probably just "shell shocked" from being moved from your lfs to your work tank....then bullied out of the pair and moved yet again to a completely different tank-your home tank (which I feel was definitely a good move for his safety and well being) Angels can have a hard time adjusting and getting along at first and definitely won't eat (sometimes for a few days to a week) until they are completely comfortable with their tank mates/situation....
Good luck hope all goes well!

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[Tolak]

If the slow to eat angel isn't eating after a few days it's time to treat with metronidazole. It's had the stress of being moved, bullied, then moved again if I'm reading this correctly. You will want a med tank for this, a 10 is fine, a 5 if the angel is smaller. You'll also want a heater capable of bringing the tank up to 90F, and a filter or air supply to aerate the water, warmer water holds less O2.

Treat with 40mg/gallon metro with a daily 50% water change & remed, tank temperature at 90F. Hold off feeding for a few days, then take some frozen brine shrimp, sprinkle on a little metro, sort of make it look like a tiny powdered doughnut. Feed only this once daily, continue treatment for 10-14 days.