They are adults, but not old. The water parameters are:
Nitrates 0-10
Nitrites 0
Hardness ~130
Alkalinity 80-120
Ph 7.6-7.8
Ammonia 0
There is a Marina S10 hob filter and a lot of plants in the tank. It is a 10 gallon and currently has the 7 CPDs, 6 Bumblebee Gobies, 2 Scarlet Badis, Neocaridina...