Cory Cats not eating

Question
Thanks for your reply.
I have a 25 Watt heater, temp is 80-82. 25% di water change weekly with gravel vacuum. Full water test, other than my  phosphate levels, nothing else is wrong. pH 6.8, Ammonia 0, Nitrites 0, Nitrates 20 ppm, KH 2, PO4 8 ppm. These two fish haven't been right since they came home from the store. I see no sign of sickness. Do they eat in the light, or do they eat at night?

Answer
Hi Lee;

Water chemistry looks good, and you practice good maintenance so that's not a problem. I forgot to tell you last time, they sometimes do eat at night.

If they look okay maybe they are just exceptionally calm little cories. Sometimes fish that aren't getting enough oxygen will be very lethargic too. Cories do take gulps of air from the top, just like bettas. They do however need oxygen provided in the water too. You might consider adding a constant flow of a few bubbles with a tiny air pump and airstone, or a very small air operated decoration. Add just enough bubbles to give oxygen, but not enough to move the water too fast. Bettas can't tolerate fast current. I think it may help. Looks cool too. ;-)

At Your Service;
Chris Robbins