That's true. All Clariidae are on the federal list. But, as stated, not all states have adopted the federal list. In fact, there are still states with no list (therefore no enforcement). So, any federally banned species within those states with either no restricted list or no adoption of the federal restricted list into their own state list are considered as being legal due to no implementation of any system to inform citizens of or enforce the law.
One prime example is Maryland which adopted the federal laws concerning snakeheads. But, only the larger non-tropical species. Maryland still allows the possession of the smaller tropical species of snakeheads with the condition that no new specimens are allowed to cross state lines (per the federal law) into the state. And, no sales/trades/trafficking of permitted species are allowed out of the state.