The nitrates were high, that’s why it died. I have an electric blue in a 10g with two goldfish, a rainbow shark, and tons of ramshorn for it to eat. I keep the nitrates low to about 15, but I’d like to think your cray would’ve tried to escape first or do something to let you know something was wrong. When I had high ammonia in my tank due to the goldfish, I came home from work to see my electric blue waiting for me in my hallway. Sadly I don’t know if my cray is male or female and the time I picked it up to put it in the tank, I grabbed the claws and it still managed to bite me so I’m not too keen on knowing the gender anymore.