Just to clarify. Dalmatian (not dalmation) is not technically a color name as recognized by the IBC. So basically you can call any fish with some spots on it a Dal. Basically what a dal is is a solid or marble colored fish with noticeable spots on it. Some part of the spots is linked with the marble gene which hasn't been fully investigated so it's hard to breed for them.
A blue fish with black dots, most likely on the caudal or dorsal fin is just a blue fish. Those black dots are throwbacks from the original betta splendens. You can find a lot of wilds with similar spots or stripes on their dorsal or caudal fins.
*Be smart.. Do your research!!*