Greetings! This is my first post here (just joined about an hour ago), so I'd like to first say thank you in advance for all your input. Almost immediately after joining, I realized a lot of the stuff I've been doing is wrong. How I have not yet killed my poor sweet Fishnesness is a miracle. So here's the deal: My 27-cent comet has, in the past 2 years, blossomed into a robust 6 - 7 inch beauty. I noticed, at least 6 months ago, that I could see red veins in her tail & fins, but just assumed the veins were becoming more visible because she was getting bigger. Also, I never tested the water for anything because I figured if she seemed healthy, she is ( I know, slap me now). A few days ago, I noticed the base of her tail look rather purplish, which was new. After researching online, it sounded like she either has something called "septicemia", or it's from her tank having a lot of ammonia. Off to Petsmart I went and got all the testing strips needed. The numbers: Ammonia: between .25 and .5 (yikes!) Nitrates/Nitrites: 0 Hardness: 300 Total Chlorine: 0 Total Alkalinity: 80 pH: 7.2 She was in a 10-gallon tank until last month, when we were given a used 29-gallon tank with some plastic plants. I washed it all out with bleach water, then rinsed it very well with Primed water. I added more gravel in addition to the gravel from the old tank, trying to keep the old stuff on top, and continued using the AquaClear 30 gallon filter I already had. The guy at Petsmart said since it's a big tank, the ammonia would be diluted more, and the 30 gallon filter would be fine. I must add, until joining this site, I'd never even heard of 'cycling the aquarium'. Also (there's more!), I've been unknowingly doing bad things to my filter: Every time I did the 25% water change/gravel vacuum, I've been rinsing out all the filter media in running tap water, then soaking it in Primed water. Yikes. I just learned today that I've been killing all the beneficial bacteria, and I'm assuming that's at least part of the reason why the ammonia level is high? More info: In addition to using Prime for the new water, I've also been using Tetra Easy Balance Plus. Someone online told me the latter product is useless, and to discontinue using it. I do a 25% water change weekly, and change the ammonia and carbon filters monthly, at different weeks. I also change the sponge every 3 months. I feed her 1 big pinch of food 2 X a day, along with some lettuce a couple times a week, and about once a week, some orange bits. I hope I haven't overloaded you with info (it sounded like the more info the better), and again, thank you from me and Fishessness for any info you might have.