disappearing

I got this little fella (blue mandarin) the other day at PetCo. There was two but sadly the other one had passed away :// I ended up getting just him. He has been doing fine in the tank, got him copepods to eat and he was eating. This was 5 days ago that I’ve had him. I haven’t seen him since...

Sorry for the long post but some opinions would be helpful in figuring this out. The past 2 weeks my fish have unexpectedly died. I have 2 ideas why but information online is conflicting. My aquarium; 90 gallons, 20 Gallon sump, its about 4 months old. I had a 75 gallon and upgraded to this...

All of my zoanthid frags starting disappearing over night and I noticed these snails a few days before I noticed my zoas gone. If anyone can ID them for me that would be much appreciated. Need to know if I need to completely wipe them out or not. Has anyone else had their zoas disappear within...