It is my first time to hear about tradenix. I think you don't have to choose them as the exchange because I think that site is new, and we don't know how good their reputations. Maybe you can try to visit binance because binance is a big exchange, and I know that many people here are trading on that site. We have another big exchange like poloniex, bittrex, kucoin, and else so you can try to look at it. I recommend those sites I mention, but binance still favored by most people here.