This is what I would do to try and make the tank successful longterm from this point. Get ready to spend money...
1. You need much stronger lighting. What you have is nowhere near enough.
2. Don't add anymore livestock.
3. Take the damsels out and give them away (try to).
4. Increase flow inside the tank.
5. Make sure your temp is steady.
6. Increase salinity and get a refractometer if you don't have one.
7. Target feed your nem (search forums for what and how often)
1. You need much stronger lighting. What you have is nowhere near enough.
2. Don't add anymore livestock.
3. Take the damsels out and give them away (try to).
4. Increase flow inside the tank.
5. Make sure your temp is steady.
6. Increase salinity and get a refractometer if you don't have one.
7. Target feed your nem (search forums for what and how often)