Empty fish crates are an item made by using a camphor crate with an ice cooler, which are purchased from Slayer Masters; up to 10 can be made per action. They are used to store raw fish obtained from shoals whilst deep sea trawling; deep sea fish can only be stored within the crate in sets of 10.
Empty fish crates are stackable when empty, allowing it to only take one space in the cargo hold of a boat. When emptying a trawling net into the cargo hold with empty fish crates stored inside, the crates will automatically be filled, with any remainders stored as normal. As each crate can store 10 fish, players can effectively store up to 10 times the cargo hold's capacity in fish by storing crates filled with fish, which can drastically lengthen a trawling trip.
Filled fish crates can only be emptied while standing inside a bank, returning the crate without the ice cooler. This must be done by right-clicking the "Empty" option whilst having a banking interface open; if emptying the fish crate otherwise, the crate will be lost.