Are clams fish or clamshell halal or haram please inform in brief?

According to our research clams fish or clamshell does not fall in the category of fish. Below is an excerpt extracted from the net defining clamshell.

Clam Fish: Despite the name, shellfish are not actually fish, but are simply water-dwelling animals. Most shellfish are low on the food chain and eat a diet composed primarily of phytoplankton and zooplankton. … Molluscs used as a food source by humans include many species of clams, mussels, oysters, winkles, and scallops.

We as followers of the Hanafi Madhab are only permitted to consume fish from the ocean, and due to the Clamshell not falling in the category of a fish it will not be Halal/suitable for consumption by us as followers of the Hanafi Madhab.