SO last week, 2 of my fish have vanished. I had 1 medium sized clown, a medium cardinal, firefish, and 2 ranford gobies all in my 16 gallon nuvo. There is no lid but I've had these fish for over 2 years now with no jumpers. Parameters are all 100% no stress the remaining fish are as healthy as ever. The clown randomly went from king of the tank to vanishing over night. then 2 days later one of the ranfords disappeared. Only new additions is a small emerald crab and also a small like half inch white crab with spots that was a hitchhiker. Checked very well for jumpers and didnt see anythign also have no pets. The clown doesnt really jump he is very bold and just drifts around in the water column kind of subtly bullying the other fish. I have no idea where they went. Also this tank is set up more like a frag tank only one rock in the whole tank that is about 1 foot tall so not a lot of places to disappear to.
