Arionum has been listed on on Mercatox.com
ARO/BTC and ARO/ETH markets are available for trading.
https://mercatox.com/exchange/ARO/BTC
https://mercatox.com/exchange/ARO/ETH
Make sure to enter the MEMO id while sending coins to Mercatox, otherwise your account won't be credited.
https://youtu.be/7aBDci9KIPo