I've been lurking around here for quite awhile picking up tips for my betta, who I got back in March. Thanks to the info on here, he appeared to be happy and healthy. The last couple times I have done water changes, however, he's started acting strange. Whenever I add fresh water, he goes from swimming merrily around to hiding in his cave or under a plant, fins clamped, not moving at all. He stays like this for about a day and then goes back to his usual self. I use tap water with Prime (2-3 drops per gallon) and make sure the temperature of the new water is the same as the old stuff, so I've ruled out those two major issues. I worry because I've had the little guy for almost 6 months and he's only started doing this within the last week or two. Anyone have any ideas what might be causing this? Should I be concerned for his health, or is it maybe just a weird behavior thing? Thanks in advance for anything anybody has to offer.
Quick rundown of my tank setup, in case this info helps: He's in a 3 gallon filtered heated tank. Heater keeps him at a steady 79-80*F, and I've baffled the filter by rubber-banding a piece of filter sponge under the outflow. I have one live java fern in there and the rest of the plants are silk. No other fish in the tank. I usually do one 50% and one 100% water change each week.