Yes, connected directly using a 12V splitter cable. Two pumps.
Not much in the way of specs available... 6-12V, 4-5W it says on the label. This are cheap made-in-China submersible aquarium pumps. From my searches on how these pumps work I know there is some form of control board; I saw mentions of analog circuits that could be used to operate these pumps; I guess this is the cheapest way so that's most likely what these pumps use.
Power supply is almost certainly of the switching type, again no data sheet or so available. Input 100-240V, output 12V DC. I can't even open it to check the internals, it's totally sealed shut.
Really hope to be able to get the money together to buy a scope... would be very helpful in so many ways, including this situation, but until then I just hope to get a good idea on what to expect from such pumps with regards to my power supply. I hope to not have to go for separate power supplies.