Mining can give you 400k-1m/hr with 85 mining, runite and the right stats/quests. However, it takes ages to get 85 mining. If you're botting, then the time it takes to get 85 mining may not really matter.
Fishing is much easier XP. All you have to do is bot, or turn your in-game sound effects on so you know when your fishing spot has moved. At sharks I can imagine one finding themself rolling in GPs. I doubt it's as profitable as runite mining though.
Hunter is probably the most painful to level up, yet the fastest. Chinchompas give a LOT of money on your way to 99 hunter but it's not necessarily fast money.
tl;dr runite>sharks>chinchompas in terms of time taken to acquire the necessary level and amount of GP/hr (runite takes forever to achieve and has the most gp/hr. chinchompas are very easy to achieve but give shit gp/hr at the minimum level)