cory cats

Question
we have 2 cory cats that for some reason in the last 2-3 days are swimming in the middle of aquarium next to glass or swimming up the corners of the aquarium.  They haven't ever done this before we have had them for over 6 months.  

Thanks in advance

Answer
Hi Devon,

Change your water asap!  No waiting.

The fish are experiencing ammonia poisoning.

This is a sure sign of dirty water, and their behavior is teh beginning of death.

It may take weeks for them to die this way, but the rest will surely follow.

Clean all filter media, and change half the water today, and half the water day after tomorrow.  Remember to always change water bi-weekly in the tank.  :)

Happy fish-keeping.