Hi, Please excuse me if I format this in the wrong way as I'm new to this forum. I'm currently cycling my 190L corner tank as a Cold Water setup (Avg temp is 20 degrees) and I have it currently setup with sand and some pieces of bogwood. I haven't yet got any plants or rocks as of yet. I am just wondering as i'm a beginner to fish keeping what sort of fish i can keep in the tank. Im also wondering is there any crabs i could have in the tank?? I had a red crab years ago in a old setup and it was excellent.

its a cold water setup with the avrg temp 20 degrees and 190L water capacity.

Thanks in advance