cool arrangement...just let you know, some crabs will devour small fish...and some fish (larger ones) will devour crabs

but this system, it appears anyway, looks more like a shrimp, crab, snail, possiblye frog and turtle (if either one is not too big) kind of set up

course fish can be placed in the tank, just be careful how you group the fish with the crabs

Nice set up. You did some nice work.
Be careful with the water since it is not cycled.
For the first month do a partial water change every week, and don't feed excess.
Even tho the tank does not need to be cycled with crabs, you don't want them sitting in toxic poison either.
Love the hand, and the sand looks good.

Thanks guys. I put two crabs in. One died. Im going to do some water changes. The crabs were kept in fresh water at the store. Im not sure if thats what killed the one. I slowly introduced them to the brackish water. I dont know. Just water changes for now. Then if the crab survives for a few weeks more crabs. If they survive than a molly.

Second crab is on his way out. I put two cheep golf fish and two fiddler crabs. Goldfish are on their way out within 3 hours of putting them in the tank. Fiddler crabs are livly as hell. They are doing great so far.

I noticed lots of bubbles in the tank. Small bubbles that are clustering in grounps and not going away. At first i was thinking that's what its like when a waterfall is used but now.... im guessing its some sort of toxic chemical. All the products i used were recommended by people who had built backgrounds before.

The one thing im guessing it could be is the concrete coloring. I dont know. Any ideas?

nope. I have never herd of this. i would love to hear.