I have a little guppy that's been hanging out on the bottom of the tank for a few days. He's been avoiding light and trying not to swim a lot. Generally lethargic. He's the same age as the other 3 in the tank and they're all quite happy and eating heaps where as he has a few little bursts of interest then goes back to hiding. He's a lot thinner than the other 3 and his gills seem to be working overtime. He doesn't seem to swim with his tail unless he really has to and I thought I saw him swimming with his gills at one point but surely that can't have been right. This evening he was floating vertically with his head up in about the middle of the tank so I figured it was time to see what I could do.
I've moved him into another tank, which luckily I set up earlier today to try to cycle (hopefully he makes it and it cycles with him), and I've followed the salt treatment plan on the guppy ailments website. Should I do anything else? He doesn't seem broken or have any ulcers but his tail looks a bit more raged than the others and the lack of action is concerning.
I'm new to this so i'm reading everything on the net and probably over-reacting.