What is this?

[Cannoy]

Not sure what this is or how to describe it and they only come out at night.

 

[cracker]

I think that's an amphipod or copapod , A marine bug that is good for Your tank and considered a delicacy by Your fishes!
Now, I expect the experts will soon give You the specifics and proper scientific names and spelling!

 

[Cannoy]

Thanks, wasnt even sure how to start researching it.

 

[chipmunkofdoom2]

I'm no expert, but cracker is spot on, it's an amphipod.

Fun fact, giant amphipods, which look just like the little one but larger, live in the ocean deep. They're kind of cool, but it's kind of scary to see those little bugs so large!

 

[cracker]

I've seen those creatures. Glad They don't get any bigger!