My daughter is 9 months old. We bedtime trained at 4 months and nap trained at 5.

We have the aquarium and found it very helpful from 3-8 months to use as tummy time entertainment. Once she figured out crawling it wasn't nearly as interesting. For my daughter, it was too stimulating to fall asleep to. I'm sure it works for some babies and it's a fantastic toy! I've recommended it other parents before. But I've always recommended it as a tummy time toy or a soothing device, not as a sleeping tool.

I don't and have never used black out curtains for my daughter. For some babies, it helps because there are no distractions. For my baby, it didn't seem to make a difference.

Currently, I have these strung where the wall meets the ceiling with poster tack around the circumference of the room. It's very soft lighting and it's not a distracting source. It's remote-controlled so I can adjust the lighting. and when she is upset and I want to distract her, it does different settings so I can make the lights.

https://www.amazon.com/dp/B07GMQ42GG/ref=cm_sw_r_apap_xeioIltLZYXrH