My flowerhorn has kind of been acting weird for the past few days. He stopped eating pellets, and it looked like there was an indentation where his stomach is, but I fed him frozen bloodworms, and he ate all of those. He also hasn't been as active, he's just been hiding by the heater. He was scraping his head trying to go under the sponge filters a while ago, but I pushed the sponge filters up against the corners of the tank so he couldn't go under them, and I think it's mostly healed up. Also, his fins have turned darker in colour after I added black diamond blasting sand to the tank. Do you think he's sick, or has he just gotten tired of the pellets? If I throw in a few pellets now, he grabs them, but then he spits them out, but he's still eating frozen bloodworms.
