I was doing my weekly 50% water change on my betta's 2 gal, and I as I was putting water back in, I noticed something odd... a spider. A small, skinny spider was sinking to the bottom of the tank. I assume the thing dropped in there from the ceiling or something. (My aquarium doesn't have a lid, but I'm hoping to acquire one soon.) Just to make sure, will a spider's being in the water harm my fish? I was just putting in the clean water when I noticed it (fishy was in his cup). Do I need to replace the water, or am I concerned about nothing?
Also, my fish's fins are still looking a bit odd. I say "still" because about a month and half ago he seemed to be sick, and his fins looked less than normal-- since then they have not looked long and flowing the way they were when I got him. He is healthy-- acts normal, excited to see me and be fed, gets regular weekly 50% and 100% water changes. I'm just wondering if there's something I can do to help his fins heal properly. I'll put up a picture if he'll hold still.
Thanks for the help!