I have four Betta fish. Three of them give me reason to believe that they are sick.
My first fish, a dark blue and red crowntail betta, started to have brown discoloration on his head. I thought maybe it would go away after a while. It got worse. So I changed the tank. Now, he's swimming in a shared 2.5 gallon tank with a divider, filter, and light. I have conditioned the water as well. So far, it appears that the discoloration is slowly disappearing. However, it still persists and half of his head is either brown or a dark grey-black with a bit of white on the bottom. This is only on his head. The other fish he is rooming with is healthy.
My second fish, a dragon scale betta, had a little bit of trouble swimming around. He would start to move and then turn sideways for a moment or two be for swimming upright again. It almost looked like half his body was bent. So far, he hasn't really, shown much more of his awkward swimming, but I was still wondering if there was another explanation for that. He is in a tank by himself.
My third, and most concerning fish, is a white halfmoon betta. I got him one to two weeks ago and he has only eaten once. Most of the time, he hangs around the bottom of the tank, nearly oblivious to everything around him. He likes to stay near or in the fake plants I placed in his tank and reacts to almost nothing. Half the time he looks like he's dead because he stays so still. Then I come back a bit later and he's in a different spot. He doesn't share a tank. I think it might be stress so I moved around the tanks so he was closer to the light and other fish for a change in scenery. However, so far, that's the only thing that's changed.
All the tanks are side by side with the larger, filtered, and lite tank in the middle. They also have plenty of decorations.
I have only had one other betta fish before these four and he lived to a ripe old age of two years with no problems so I am at a loss. If someone could help me with either of these fish I would be very grateful.
Thanks for reading!