Here's the info on Shark's cage - before and after the changes it just went through, and the things that stayed the same.
3 or 3.5 gallon tank (I believe 3 flat, but I do not remember)
Shark (Obviously xD)
Heater permanently set to 78 degrees Fahrenheit.
Gravel+some rocks, sea shell.
Tiny sponge-filter with I believe carbon? Not sure how effective it was but it seemed to work, at least the sponge part. Had it for a while, but I needed a filter change-out and couldn't find a place to buy one, so I just kept rinsing it out.
Located below an east-facing window that recived not too-much light, so he wasn't in direct sunlight (there was a large sugar maple in front of the window)
--I went shopping and got the following:
Prime water conditioner (I was using stress coat before)
A Hydro Sponge filter for up to 10 gallons
two live plants: Java Moss and a little stem and leafy one I forgot the name of (>.<'' crud.)
I moved him into the living room, since he'd been tail biting and I think it stemmed from boredom+he was used to seeing me a lot, and now that I'm not at the dorms and at my friend Linda's for the summer, I've been out and about doing a lot, and he didn't often see me besides feeding time. Now that I'm conscious of this, I'm going to be spending more time with him, and the change in the living room I think will help him keep interested.
I did a water change before moving him and adding in his new sponge filter, which I rinsed. Also, Linda's water here is well-water, I have no idea the PH. He was doing fine before it seemed - I tested his ammonia level with a kit I just got today, and it read 0.25ppm.
A few hours after the change+plants, I checked it out of curiosity to see what it went down to...
...but it went up instead! I believe it reads 0.5ppm, though I could be wrong since I find it a little hard to accurately match the color in the test tube to the color on the stripe. Oh, there's another key detail - yes, I am using one of the test-tube testers.
I plan on doing an immediate water-change before going to bed, but this alarmed me. I have no idea the ammonia levels in the past, though I've not seen any burn marks on Shark and I do not believe any other symptoms - though recently, his fins have started curling, and I've heard people say that is either from cramped space (which is not the case here, I do not believe), hard water, or high levels of ammonia or long exposure to it.
I did slack on my water changes since I had a bit of a hectic week (hay making o_o), but I always did a 50% if not 75% once a week. I intend to move my schedual back to 5o% twice weekly, and I saw someone recommend a 10% daily...?
Any help would be greatly appreciated!! I'm still such a newbie to fish keeping, and you guys on here have already helped me so much, so thank-you for your time and knowledge.