IOTA is not on Bittrex yet, but is already had its great growth and still has good potential in the future. On Bittrex, they offer another DAG based crypto - Byteball, compared to growth of IOTA (10bil USD marketcap) or Raiblocks (2.8bil USD marketcap), it has the growth phase still ahead (680mil USD marketcap). And compared to these 2, it has the most advanced eco system with working wallet, smart contracts so this has good potential.