I think 2 or 3 would be fine in a ten gallon tank. I would provide filtration for these aquatic salamanders, either a sponge filter or a submersible Marineland Dueto (it can be turned down to a slower flow than a lot of other submersibles). Make sure you have a escape proof cover and some place where they can climb out of the water. I like using floating Styrofoam trays for this. I remember feeding this species various fish foods, but it's been a long time since I have kept any. So, hopefully someone more qualified on their husbandry will respond.