We are very new to keeping fish, indeed out tank , after all the fill, treat and wait, only had fish entered 3 weeks ago , which were 3 make guppy. Since we have added 6 neon. Today have noticed one of my guyot has spent a lot of time at top of tank in a corner. It's back spine has become very curved (downward) . Can any one tell me if it is likely to be deseased or just poorly or on its way out?do I need to take it out, or can I keep it in same tank but in a bag (like when you adjust new fish?) so as to keep it at right temp? I am a bit lost?