There are lots of ways to earn some cash in Old-School RuneScape but none are more relaxing than a nice bit of fishing. The strategies for fishing do change slightly as you level up which results in better locations, more experience and even greater profits as you level up over time. It's a nice relaxing way to play the game to earn some OSRS cash and it's a great way to spend your time in the game.
Join the Fishing Guild
If you want to do plenty of fishing then joining the Fishing Guild is a great idea! The base is located North of Ardougne however, you do need to be level 68 before you can access the guild. So, you will need to spend some time playing the game before you can get access to this guild. You can also use different boosts such as Fishing Potions or Fish Pies to boost your way into the guild which technically means, you can get inside at level 63 at the lowest. If you use that method to join then the Fighting Guild won't kick you if you drop below level 68 as well.
Once a member of the guild, you will get access to the Minnow Platform on the Northern Dock however, you do need to have level 82 Fishing, finished the Fishing Contest Quest and also be wearing the Anglers Outfit when talking to Kylie Minnow. Every 15 seconds, the Minnow spot will change so players need to pay a lot of attention to keep catching them. You can trade 40 Minnow to Kylie in exchange for 1 raw shark. While you can fish for sharks yourself at level 76 using a harpoon, you do need to be level 80 in Cooking before you can cook them into food that will heal 20 HP at a time. You can also sell them for a decent amount of OSRS gold so you can keep catching Minnows to earn some good money from the trade.
What are the best quests and locations?
Early Game: Sea Slug Quest (Level 30 Firemaking), Draynor is a good location for Shrimps and Anchovies, Barbarian Village + West of the Fishing Guild are good for Trout and Salmon
Mid Game: Lobsters can be found near the Fishing Guild and Catherby, complete the Swan Song quest to get access to the Piscatoris Fishing Colony to find Monkfish.
Late game: Barbarian Fishing but you can only catch Leaping Trout at level 48 so it's better to eait until level 58 at least though you can catch Leaping Sturgeon from level 70 Fishing, you can catch Sharks with harpoons and the best spot is inside The Fighting Guild. You can also get Swordfish and Tuna at Musa Point or the Corsair Cove Resource Area if you complete the Dragon Slayer quest.
What about earning Old-School RuneScape money?
As you increase your Fishing level through fishing, you will end up with lots of fish in your inventory. They can all be sold to vendors or to other players who want to use them but don't want to spend the time fishing. Since you need to keep fishing to level up, this means you will have plenty left in your inventory to sell even if you do want to use some of it. All the fish can be sold so you can a lot of OSRS cash just through fishing. Sharks, Monkfish and Lobsters will net you the most profit but the methods for fishing them a bit slower than with the other species of fish.