In a deep fry pan add a little oil. Turn on the heat to med. When hot, add in the chopped garlic. Lightly fry it.
Put in the fillets. Frozen or thawed is fine. Let the fish fry a little. Salt and pepper the fish.
Add the can of diced tomatoes. And drizzle the fish sauce on top. Sprinkle some fried shallots on top.
Let the fish simmer in the sauce uncovered until the fish is cooked through and the sauce reduces. If theres a lot of water from the frozen fish turn the heat higher once fish is cooked.
Roughly chop some cilantro.
When the fish is about done. Sprinkle the cilantro on top.
Turn off the heat and you're done.
Serve it over rice. You're welcome.