POD Population kinda low

[GoPitt88]

So I have a 3 year old 55 gallon mixed reef tank, fully stocked with 8 healthy fish and a mix of coral. I've recently noticed that my POD population seems quite low! Really low! I checked last night with a red flashlight, and I barely saw anything scurrying around. I can remember the days when my tank was crawling with little critters. What's going on? Can it just be a natural low point in their natural cycle?

 

[EW_Fish]

What are your 8 "fish" ? That many in a 55g could be the reason why you don't see many critters

 

[GoPitt88]

What are your 8 "fish" ? That many in a 55g could be the reason why you don't see many critters

A pair of mated snowflake clowns, a pair of blue green chromis, a 6 line Wrasse, Midas Blenny, diamond goby, and a Coral Beauty. I've had them all for nearly 2 years....I've just recently noticed the decline in numbers. Though, there is something else I've noticed.......a spread of vermetid snails on my live rock. Could they be the culprit? If so, how do I get rid of them?