The Catfish area is the area that you can grind till above 50+. Once above that, with enough AP/DP you can do to Manes or Helms in Mediah region to level. Alternatively, you can ask others to Powerlevel Boost you to Lvl 56 instead in Group Chats if you want. 

Hi, I would suggest doing MQ until you reach 50+. It's the easier, quicker way to level that also comes with rewards. I personally do MQ, with a bit of dummy training. Then from 60 to 61 I did  side quests with the Chenga tome.