Alright, I've had fiddler crabs before, and sadly the only outlet to buy them at in person is walmart, at least for me. I'm not particularly happy buying from them, any fish I've ever bought from them has died and I've been an aquarium hobbyist for years. Anywho, I am going to purchase a couple of their fiddler crabs, but I want to make for sure this time I'm doing everything right (however they may still die)

I'm setting up a 10 gallon tank. I'm going to use a base layer of natural pebble gravel to line the bottom, also I want to make it slope up an inch or so high on the side where dry land will be. On top of that I'm using natural, chemical free sand sloping it so that habitat is evenly halved, well as close as I can get it. I want the sand to go as high as 3 inches, maybe four, including the inch layer of pebbles below, while my water will not be as high.

I do realize I need to rinse the sand and gravel with de-chlorinated water to remove dust or anything else.

So far I have a 5 in 1 submersible filter, hydrometer, heater with thermostat, submersible air pump for oxygenating the water better. I keep getting researching but still haven't yet figured out if I need to use aquarium salt or marine salt. I figured since they are brackish water creatures I would use marine salt.

This is the same set up I used before, except that I used an 80 gallon tank with a wave maker set on a very low setting so that there was a mild current, so mild it allowed the crabs safe entry in the water and out. I used the same filter system I listed above because at most there was only ten gallons of water in the tank, and the land was evenly split with the water, going about two and a half feet high with dry land. I had 9 fiddler crabs in there and they lived for 5 years. I'm positive they died from old age because they become slower in movement and even their little mating dances became less and less. I do know they did mate but I realized it was near impossible to see their eggs through. Mine always burrowed, the males were extremely territorial when it came to their own burrows except with females.

I still have my 80 gallon but I have java moss growing along the entire back wall of it and its filled with water but no fish, I gave that tank to my husband who's entirely new to keeping fish but learning lol. So I can't use that tank anymore.

He's wanting to go smaller at first and get some fish. So I figured we'd switch tanks and he can start off small like he wants, then when he's ready to move up we'd switch around or hopefully I would have found a tank close to the 80 for my crabs, or him a larger tank so I can keep the one their going to be in.

I know I bounced around with topics but my main concern is if a couple of crabs in a 10 gallon tank like I've described will survive? I've only had success keeping them alive by giving a large inclosure with a wave maker and deep sand so they could burrow properly.