The coin must be trading on an exchange supported on Delta
Sometimes coins have a different shortcode than some exchanges
Sometimes, different exchanges use different shortcodes/tickers for some coins. For example, in the past, ETHOS is ETHOS in Delta but BQX on Binance, or Stellar is XLM in Delta but STR on Coinspot, etc. In such cases, it helps to search for the coin by its full name.
PRO TIP: Ensure that when you are searching for a coin, you are looking for this under the crypto dropdown. Also, check that you haven't collapsed the crypto section of the search page.
PRO TIP 2: If you are adding a manual transaction and you are only seeing one asset class (and is causing you not to see the coin/token you are looking for), you need to disable this asset as the default page when adding a manual transaction.
PRO TIP 3: If you still can't find a coin, please add your request for the addition of a new coin to our coin request page.