Lethargic Betta with Clamped Fins

Feb 26, 2017
Hi everyone!

My betta has been acting weird lately. I noticed yesterday that all he does is lay around either on his plants or on the gravel and his fins are clamped. When he moves, he tends to dart around.

I tested the water and found:
Ammonia - between 0 and 0.25 ppm
Nitrites - 0 ppm
Nitrates - around 40 ppm
pH - around 6.8 to 7.0

He currently lives in 5 gallon, heated aquarium that was cycled prior to acquiring him. I also have anacharis plants in there.

I performed a 40% water change after testing his water yesterday. He doesn't look any better.

What should I do?