Severum's weird behavioral change

[gecko_41]

I have a turquoise severum, about 2 years old. He is in a 55 gallon tank with some rainbows and clown loaches. He has always been rather shy, but after I had him a year he actually got to where he would eat out of my hand. Then about a month ago he started acting weird, getting spooked very easily, stopped eating out of my hand, and now he just kind of cowers in the back corner of the tank and hardly eats.
I do regular 15-20% water changes, and keep the temp between 78-80. I have some plastic plants in the tank, but no rocks, I took them out so he wouldn't damage himself running into them when he got spooked by some movement in the room.

I am baffled by this sudden change in behavior. I am assuming he doesn't feel well, but I don't see any visible signs of disease. Anybody had a similar experience, or any ideas of what I can do for him?

[peifc]

How often do you change your water? My severums do that every time after I have changed the water. Would take them awhile to become their own self again. Some people mentioned in aother forum that this behavior can cause by the light bulbs being too bright.

However, I have another time that occurred with my Severums and Blood Parrots. They ran every time they see a movement in the room. Then I discovered they ran because they felt a big vibration (someone walking heavily, especially my neighbor who walks like elephant). I decided to turn off the light to see if they acted that way as well. And it seemed with the light off...they were more comfortable. I turned on the light when it was feeding time. Then I turned off the light again. I did that for a while. So when the light is on, they believe it was feeding time. Now I have the light on all the time, they still out and swim around.

[gecko_41]

I usually change the water every 3-4 weeks. The weird thing is, I've had him two years, and he just started doing this recently. Nothing has changed in the room or anything. The tank is on a far wall in the living room and there's hardly any traffic in front of it. And we have no kids that might be tormenting him. I know Severums are shy fish, but this is in the extreme.
I just have regular flourescent bulbs, not the gro-lite kind. I'll try reducing the light, thanks for the suggestions.

[DarthV]

I'd step up your waterchanges to once a week... as a fish fgrows larger, it will be eating more food and producing more waste.