I have 2 fantails in a 30 gallon tank I've had for several months now. They've always acted fine, eager to eat when it's time (and when it's not) and whatnot. The past day or so however they seem to be nervous or scared acting or something. If you walk by the tank (it's in a very low traffic area as it is) they don't come up to the front looking for food like normal, but dart off and hide in a back corner. I was trying to observe them last night and one would seem alright then suddenly dart around the tank, then just stop and hang around. The other tends to sit on the bottom and hide. They both came out and ate though when they were fed. I promptly checked the water parameters: Ammonia 0, Nitrite 0, Nitrate 10, pH 8.2 (this is normal, as it is out of the tap). I gave them about a 20% water change and let them be for a bit and went to research. The light over the tank is kind of sketchy so I didn't know if it could be some kind of electrical current getting in there, so I switched that out to one I know is fine. Then read about heavy metal poisoning. There are colored glass pieces in the tank so I wondered if those might be causing problems somehow. I scooped them all out and did a 50% water change and left them over night. They don't seem to be acting any better or worse today. Physically, they appear perfectly fine, not clamped or anything. Anyone have any ideas what might be going on?