I don't know if its ich or finrot or what. The spots appear to only be on the fins. I'm trying to grab a few pictures so you guys can see it more clearly.
Relevant tank info:
Ten gallons, contains 8 tiger barbs. Previously were two others, one died three days ago, body removed intact, other died approx. 2 weeks ago, body heavily picked at before it was noticed- both deaths were from the same store, remaining fish all from a different store (from which I have never had any deaths)
Its my first tank and I've had it a couple of months now, and it appears (to my inexperienced eyes) to be fully cycled. I did a 30% water change yesterday (which I do every week, plus or minus a day or so) and I changed the carbon filter but NOT the sponge filter.
My questions boils down to, what should I do? About half the fish are affected. Should I raise the tank temperature, do a large water change, what? I thought about isolating the sick fish, but in what? I don't have another tank, and I'm not sure how to heat my bucket. Also, I unfortunately am not in a position to go to a store to pick up any medications for perhaps another 3-4 days.
Any advice is appreciated, and if I've left out anything I apologize. Working on getting some clear pics so you guys can see for yourselves.
Edit: I'm pretty sure I've been overfeeding them recently, and I've had a couple of plants dying due to poor lighting, which I've removed from the tank as soon as I've noticed them.