Fish prices can vary widely based on factors such as rarity, demand and market conditions, weather or volcanoes. According to my most recent knowledge update in January 2024, here are 10 fish species known for their high market value:

Tuna (Bluefin Tuna): Bluefin Tuna, especially the highly sought-after Pacific Bluefin Tuna, is known for reaching exceptionally high prices at fish auctions. In some cases, a single fish can be sold for hundreds of thousands or even millions of dollars.
Koi Fish: Some prized Koi varieties, particularly those with unique color patterns and markings, can command high prices in the ornamental fish market. Exceptional specimens have been sold for tens or even hundreds of thousands of dollars.
Arowana: Certain Arowana species, such as the Asian Arowana, are considered ornamental fish and can be quite expensive. The high-quality and rare color variations contribute to their elevated prices.
Platinum Arowana: A specific color variant of the Asian Arowana, the Platinum Arowana, is known for its silver or platinum-like appearance. This rare coloration can make it one of the most expensive aquarium fish.

*Related: Top 10 smallest fish species in the world
Peppermint Angelfish: Native to the waters around Hawaii, the Peppermint Angelfish is a rare and strikingly colored species, contributing to its high market value among marine aquarium enthusiasts.
Masked Angelfish: Another expensive angelfish species, the Masked Angelfish is known for its distinctive black mask-like markings on its face. It is found in the waters around the Marshall Islands.
Freshwater Polka Dot Stingray: Some species of freshwater stingrays, particularly those with unique polka dot patterns, are highly valued in the aquarium trade, with prices reaching into the tens of thousands of dollars.
Clarion Angelfish: Native to the waters around the Revillagigedo Islands, the Clarion Angelfish is a rare and colorful species that can be highly sought after by collectors.
Wrought Iron Butterflyfish: Found in deep waters around the Hawaiian Islands, the Wrought Iron Butterflyfish is a deepwater species that is both rare and expensive in the aquarium trade.
Golden Basslet: The Golden Basslet is a small and brightly colored reef fish that is native to the Caribbean. Its vibrant appearance contributes to its high market value.

Judging of fish may not be accurate and new species or color variations may attract attention in the market. Furthermore, regulations and conservation efforts play a role in the value of some species./.

FAQs:

What's the most expensive saltwater fish?

The peppermint angelfish

The peppermint angelfish is known as one of the most expensive fish in the world with $30,000 being the highest listed price. And there is excellent reasoning for it! Collecting these fish requires a specially trained diver to reach nearly 400 feet down into the ocean.

What is the most expensive fish in Japan?

Bluefin Tuna

In Japan, Bluefin Tuna it is a delicacy that is in season during winter when it accumulates fat. The Smithsonian.org calls Bluefin Tuna the world's 'most prized and valuable fish'

Which is the most expensive fish to eat?

The bluefin tuna holds the title of being the most costly edible fish on Earth. These fish have large, torpedo-shaped bodies that are almost circular in cross-section. In their natural environment, they have a varied diet, eating a wide variety of fish and invertebrates.