Yeah, that's a red-eye Tetra. They're fine. But the issue you still have is that Tetras are schooling fish. ALL Tetras, ALL Danios, ALL Barbs, they're all schooling fish which means you HAVE to have at least 5 together in one tank to be happy. This is where your issue first came about; your tank is overstocked severely and now you have a single Tetra that will not do well because he doesn't have a school. Same goes for that spotted cory cat, cory cats will NOT school with other species of cory. You need to have all the same type of cory for them to be happy and healthy. I will not be surprised if your tank gets ich again. I don't mean to be harsh but you've basically disregarded everything I've told you. I will no longer help with your fish issues, I will give advice on plants if you need it but I don't want to waste my time with someone who won't/can't learn. I'm sorry.