Recipe Tip You can use any white, firm fish for this recipe like seabass, cod or tilapia. Share your version of this recipe What is your variation of the herb fish? Share your version of the recipe and let us know. Frequently Asked Questions What is the best Indian substitute for thyme? You can use finely chopped basil for the herb fish if thyme isn’t available. How to secure the fillets if I do not have a cooking string? You can use wooden toothpicks if a cooking string isn’t available. However, make sure to soak them in water for a few minutes before use to prevent them from burning.