Is there any kind of salamander I could keep in a heated 40 litre/8.7 gallon tank or is it too small?

I have a fishtank I'm not using- I have four African Dwarf frogs right now in another tank but I'd love to get I to salamanders too. The heater I have only heats the water but I'm willing to buy a heat mats and/or lamp. But I honestly don't know where to begin with salamanders, I've done some research but the information I've found is pretty limited. I live in the UK so I also don't know what's available here