Unknown Decline In Snail Population

[Tnops]

I have noticed a drastic decline in my tank's snail population recently. There used to be many many trochus and collonista snails in this tank, constantly breeding and being out in the open on the glass for many months. Now suddenly, there are only a few to none left. I currently have a pretty bad cyano problem but I'm not sure if this is linked to this. I have soft and lps corals in this tank and all of them are doing well. What might be the problem here?

 

[blaxsun]

1. Are they getting fed enough?
2. Are there any predators that might be availing themselves to a prepackaged snack?

 

[Tnops]

1. Are they getting fed enough?
2. Are there any predators that might be availing themselves to a prepackaged snack?

I never feed them, I added a melanurus wrasse recently which only comes out for half of the day, making him hard to feed but it is still not skinny

 

[Timfish]

As hinted above if you had them reproducing they may have exhausted their food supply. I've never heard or read anything on hte subject and this is the opposite problem but they may be reaching the end of their life expectancy and if something is eating their eggs or juviniles they might not be a self sustaining population.