Are these fish compatible? 2

hey guys!
so for the last 15 years I have been dreaming of having this perfect tank with

A snowflake eel who is most peaceful at times but when the prey comes to him he STRIKES and eats the fish. Eels have been my favorite fish ever since I was a little kid.

A comet grouper (marine betta) who is mostly shy and scared and mimics the white mouthed moray but when a small guppy comes swimming by he wraps his tail around and devours the fish.

A tomato clown for his courage to break up fights from my two damsels in my old 20g and majestically eats his pellets. Peaceful but territorial. (R.I.P 2 damsels died from ich)

A green spotted puffer who snatches small defenseless snails and munches on them like a fat kid eating chocolate ;D

A dwarf zebra lionfish who quickly chomps down on a goldfish with nothing less than a tail sticking out. Beautiful yet deadly

A pincussion sea urchin the way they look is amazing and I have always loved seeing them on family vacations. is a great clean up crew for predator tanks.

A group of dwarf hermit crabs that always cheer me up
I was once taking care of a friends 30 gallon tall tank and he had this huge ancient piece of live rock of a coral which I had left a pellet on, so I watched 2 movies and came back just in time the hermit crab climed up the live rock and right when he got on the very top he fell over and went back to the bottom I laughed for a good five minutes. One of the wrasses ended up eating it. These things are fast for food!

A Horseshoe crab which I know don't live long but I have been researching them since I was a kid and I think I know how to give them happier lives

A Turbo Snail which have helped me in so many of my algae outbreaks. In one of my first aquariums he ate so much algae and became so fat he could hardly move anymore ;D But he was still very cool with his clam on his shell.

But I feel I'm missing something to complete the tank, it has been bugging me for the last 2 years and I still can't decide. I have a 55 gallon filled with caves (60 pounds of live rock) and my first fish (the tomato clown) is in there along with 3 hermit crabs. The tomato clown is being moved to a 30 gallon and is too big for fish too swallow.

What do you think?

 

Well, I think unless it's feeding time, you're not really going to see these fish around much. Maybe try to find something that is free swimming?

 

IMO you would need a larger tank and some serious filtration to keep all of those fish alive in the same tank.

 

I think you are going to need a larger tank.You are quickly going to discover that unless you can seperate what you "want" from what you can "have". You are setting yourself up for failure and the death of the fish you love. Predator tanks can become extremely dirty. Adding alot of them to a small tank usually ends in disaster. Make sure you research each fish/invert thoroughly before attempting to add them.
Green spotted puffers start off life living in brackish water. Only when mature do they tolerate full salinity in a SW tank. They can also be highly aggresive to other fish.
I would choose between the Lion,Betta or Eel. While one of these should be O.K. in your tank all three would not.IMO
The addition of the Tomato clown first may or may not be a problem but keep in mind these can be highly aggresive especially with new tank mates.
I would also not put a Pincushion Urchin in a tank with an Eel for fear of it becoming injured by it.
Horseshoe crabs do not do well in captivity and are one of the creatures I believe belongs in the ocean.