I've been trying to help you out as much as i can here but its time to get real here. The ich stands a very good chance of spreading to you blenny. Your fire shrimp probably looks sick because you lowered the salinity in your main tank and inverts do not tolerate lower salinity. Here is what you need to do. Very slowly over a couple days raise the SG in your main tank back up to a normal level. In your QT tank match the Ph, alk, temp, and SG of your main tank. Move the blenny to the QT and leave your main tank fishless in order to kill all the ich. Once you have done this then you can kinda start fresh and think about what you wanna do next. I saw you started another thread about putting in your next fish. I know you said you are going to wait a while but i just want to advise that that "while" needs to be at least 6-8 weeks or you will just give the ich another host. While you are waiting for all that make sure you are doing regular water changes in the QT which will keep the levels in check and do a lot of reading and research. I cannot stress the reading enough. It will save you a lot of trouble in the future.