marine fish options for a 40-gallon tank

[biteon]

I've got a 40 gallon tank just collecting dust and I'm thinking of converting it into a marine setup. I'd love some suggestions on fish species that could coexist in this tank - the thing is, I'm used to keeping predators and oddballs, so if you could throw in some ideas that include those, I'd appreciate it. I know most oddballs and predators aren't exactly fond of friendly, less aggressive species, but I'm up for the challenge.

Also, I've had some experience with live rock and sand, but I'm not sure how to properly care for and clean reefs. And to be honest, I've always struggled with cleaning the sand - I can only imagine how much more difficult it'll be with a reef in the way. Any tips on that would be great, thanks.

[fleeton]

Oddballs and predators for a 40-gallon tank could include frogfish and eels, but I'd also consider a Peacock Mantis Shrimp - they're pretty unique and get quite large, around 5 inches or more. Some small triggers could work for a few years too, just keep in mind they'll eventually need a bigger tank. I wouldn't mix these with most other fish that fit in a 40g, they'd likely become expensive meals.