Young and still immature, the cryptocurrency markets are the perfect playing field for arbitrage traders because low liquidity in some exchanges or trading pairs (difference in supply and demand across exchanges) may result in significant price fluctuation.
While high-frequency traders in the traditional markets battle for every thousand, high single-digit - and even low double-digit spreads - are emerging daily in the cryptocurrency markets.

Nevertheless, it is essential to understand that when markets have some discrepancy in pricing between two pairs, there isn't always a guaranteed arbitrage opportunity.
Often transaction costs may eliminate the benefits of the possible arbitrage opportunity.

Even some of the most liquid cryptocurrencies, such as Bitcoin, can have price spreads of up to 10% across different exchanges due to the difference in demand, a lack of pricing regulation, and difficulties trading between some exchanges.
Arbitrage opportunities will exist if exchanges are isolated. It doesn't matter if prices go up or down: the more they fluctuate, the greater the arbitrage opportunities!