Hi, first time poster, its a long story (happy to explain if anyones wants me to) but I've ended up with 6 coldwater fish and a red claw crab (originally 3 now 1 
). I wasn't expecting to be a fish owner right now and I'm trying my best to learn how to make sure they have happy lives! The fish now seem fine but I've lost 2 red claw crabs, trying to research they seem to need Brackish water instead but my local fish shop is adamant that because they have been bred in coldwater thats the best environment for him now and to move him to brackish would harm him but I dont understand why 2 have died (I dont know if its the water or the fish attacking although they've never bothered with any of them from what i saw). Can someone please help me with what I should do? I'm happy to buy and learn whatever is needed but I don't like the thought of him not being in the right environment (and feel terrible about the other 2). I did buy 'crab islands' so hes got somewhere to breathe but he literally spends all his time there, now and again will dip in the water but not for long and I haven't seen him on the tank floor since I bought the crab Islands. I dont really trust the shops advice as they said red claw crab are fully aquatic but literally every article I've read says they need somewhere on land.
I just need advice on if he should be moved anyway (I.e if he's not supposed to be with the other fish) or if he needs to be moved to brackish water or if im just totally wrong and its something else. Also if a new tank is needed would a 50l be enough or would he be better in somewhere bigger/smaller? Thanks for reading my ramblings and for any advice anyone can give! I've attached a picture of the tank ive currently got - 105l tetra starterline
). I wasn't expecting to be a fish owner right now and I'm trying my best to learn how to make sure they have happy lives! The fish now seem fine but I've lost 2 red claw crabs, trying to research they seem to need Brackish water instead but my local fish shop is adamant that because they have been bred in coldwater thats the best environment for him now and to move him to brackish would harm him but I dont understand why 2 have died (I dont know if its the water or the fish attacking although they've never bothered with any of them from what i saw). Can someone please help me with what I should do? I'm happy to buy and learn whatever is needed but I don't like the thought of him not being in the right environment (and feel terrible about the other 2). I did buy 'crab islands' so hes got somewhere to breathe but he literally spends all his time there, now and again will dip in the water but not for long and I haven't seen him on the tank floor since I bought the crab Islands. I dont really trust the shops advice as they said red claw crab are fully aquatic but literally every article I've read says they need somewhere on land.I just need advice on if he should be moved anyway (I.e if he's not supposed to be with the other fish) or if he needs to be moved to brackish water or if im just totally wrong and its something else. Also if a new tank is needed would a 50l be enough or would he be better in somewhere bigger/smaller? Thanks for reading my ramblings and for any advice anyone can give! I've attached a picture of the tank ive currently got - 105l tetra starterline
