How do you know that they are viable/not viable?Nothing, parents will look after them, obviously the eggs aren't viable. Sometimes takes many batches before they are. Could be they just aren't mature enough, or many other factors like water conditions. If eggs turn white after couple days they aren't fertilized. Really not much you can do, waiting game and keep trying.
Good eggs will stay clear/amber colored.How do you know that they are viable/not viable?
Yeah it’s a community tank and it has fire eels and gymnothorax polyurandons, but they are always in their pipes and crevices, even at night.Are the eggs staying a bright white? Or are they turning a tanish color?
If bright white they are not fertilized
If tan then they are fertilized. .
If the parents don't feel secure, they will eat the eggs to recycle all that energy instead of letting others..
Any other fish in the tank?