Depends what kind of tetra. I heard that black diamond tetra can be quite nippy if not schooled. Though if you don't have any problems with the platies in there then the swordtails should be fine. You could probably get mollies too.
please check ur stocking level by going to " formula used for stocking fish "
"used by DICK MILLS" check out how much room u have left!!!! tthen its my advice to get tow more tetras u need at least 6!!! thats if u have room and then u can see weather or not u have room for them but they would do fish in the tank and btw they twice as big or long than platies!!!
I am kinda new to this but it sounds like ur 10 gallon tank is pretty full. Unless you upgrade to something larger I wouldn't suggest getting more fish.
I am kinda new to this but it sounds like ur 10 gallon tank is pretty full. Unless you upgrade to something larger I wouldn't suggest getting more fish.