My tank is 2.5 gallons with a filter,heater and thermometer and I do water changes usually 50 to 75% once a week sometimes sooner but no later than once a week. My snail died but I currently have Armani in a "hospital tank" which is really just a big glass vase but it's nice and wide and is I'm guessing 1 gallon. I have his heater and thermometer in with him and this morning he ate with no hesitation. He does have fin rot and after more research I don't think he has hole in the head. I think the gray patch on his head is from a fungus or some kind of bacteria. I put some solution in his water that is completely natural and kills any kind of bacteria and can't hurt him and it seemed to help. earlier last night he was staying at the bottom of his vase and only swimming up for air and then going strait back down but a little bit after I put the solution in his water he perked up and is now swimming around and acting completely normal. Last night he ate 2 pellets and a blood worm. when he ate the pellets last night he wouldn't come up to eat them he just ate them when they sank but when I put in the blood worm he swam up and ate it. This morning he ate 3 pellets with no hesitation what so ever and is acting like I said normal. His fin rot has not worsened since last night and neither has the patch on his head. I am going to get some treatment for fungus and fin rot today and continue with the solution and see if that helps. I am also going to clean out his 2.5 gallon tank entirely and rise the gravel and plants and change the filter cartridge and rinse the filter and wipe the acrylic and everything to make sure it's totally clean.