Just came home from being out this weekend (Friday through Sunday) and have 8 dead fish. (3 pictus catfish, one siameese algae eater, 2 guppies, 3 tetras) Survivors are one opaline gourami, 4 diamond tetras, 2 black and cream tetras and one guppy. Here are the facts: 40 gal Planted established tank of 2.5 years with CO2. Water changes 20-25% once a week religiously. Canister filter fluval 206 cleaned once a month, mostly only change the carbon filter every other month and change the polishing pad monthly. Usually just wring out the sponges and reinstall. This last filter cleaning I replaced the sponges just because they were original (Canister filter been on the tank for 18 months from HOB filter) Water test results: 78 degrees F, pH 7.4, kH 20 dkh, ammonia 0.25, nitrite 0 ppm, nitrate 40 ppm. The gourami has little white spots on it like ich, diamond tetras look like a million bucks. Guppy is swimming like its about to go next with a white fluffy stuff off its side. My questions or bad assumptions: i have ich likely but has anyone experienced a die off this bad from it? Its over half my stock in the tank! Is there anything else that comes to mind? Did a water change tonight and going to keep it up daily for a week with some elevated temps to get the ich out. Any other suggestions if I have other diseases? Thank you in advance!!!