BrightOrange

Of course! Thanks for the reply. Here's the whole tank. The pleco is hiding in his log, and in front you can see a slice of cucumber on a stainless steel fork, which is for the pleco. I remove and replace the cucumber everyday. Although not a goldfish, here is a picture of my pleco, so you can see the white specks on his fins that I believe to be Ich. Several of the Danios also have these ich spots. I am now treating the tank using Kordon's Rid Ich Plus. I also just bought a heater today, so I will heat the tank to 86 degrees and hopefully cure the ich faster. When we set up this 75 gal tank, we brought over the filter, the tank decorations, and the gravel from our 40 gal tank. I sterilized all of it using boiling water before adding it to this new tank. We wanted plants in the new tank, so we put in two bags of CaribSea Eco Complete substrate for the plants, and then added the sterilized gravel and decorations. Where I think we went wrong is that we added the Danios too soon? They are probably the culprits for bringing the ich, I suspect. The third picture is my goldfish where he is currently, outdoors in the stock tank. Once I cure the ich, do you think I could bring my goldfish back inside? We've had him for three years and I just love looking at him. He started as a 17-cents feeder fish in a 10-gal tank, upgraded to the 40-gal when he grew, and now I was hoping this 75-gal tank would be his home for years to come. Any advice would be greatly appreciated!

Okay so I ended up moving the goldfish to a hundred gallon stock tank outside and he is already looking much better. The redness on his fins is fading and he is much happier out there. I guess he just wants to be an outdoor fish. The pleco also seemed to improve after I relocated the goldfish, but then I noticed a few of the Danios developing ich. So now I'm treating the 75 gal tank for ich. My guess is that the ich made the goldfish injure himself by flashing against the rocks, which caused the bloody fins and tail. His fins and tail also look a bit ragged. I'm hoping they will heal.

We set up a new 75-gal tank two weeks ago for our 3-yr-old, 9-inch comet goldfish, 3-yr-old, 11-inch pleco, and 20 glofish Danios. Tank has live plants and two filters, one rated for a 75-gal tank and the other for a 125-gal tank. Water test shows: 0 Nitrate, 0 Nitrite, 75 GH, 0 Chlorine, 80 KH, and 7.6 pH. Water temp is 76 degrees. Two days ago, my goldfish and my pleco stopped eating and became lethargic. A few times, I saw the goldfish flashing himself against the gravel in the tank. Yesterday he developed red, irritated-looking veins on his fins and tail. As you can see in the photos, his fins are now very red. I suspected ammonia stress and did a 25% water change last night, and another 25% water change this morning. The Danios have been completely fine the entire time, showing no symptoms of stress. Should I relocate the goldfish (and the pleco?) to a different tank, or just continue with water changes?