Killer Java Moss?

I have a 10gal tank with endlers live bearers and cherry shrimp. I have a sponge filter and a HOB (with a sponge over the intake) I have massive amounts of java moss; it takes up 2/3 of the tank. It would be closer to a basket ball then baseballs or golfballs. There is enough that even a couple cherry shrimp make it to adulthood even with fish and weekly gravel vacuums and 30% water changes. The tank is fed finely crushed flakes twice a day, but there is always food left over that eventually sinks and is consumed by the waiting cherrys. ammonia is zero, nitrite is zero, nitrate is 10-15.

The tank has some gravel from an established tank that i added when this tank was cycling. It is not enough to completely cover the bottom, but like 2/3 has a thin layer. I left it because the shrimp liked it.

I know i overfeed, but my mom accuses me of being cruel if i feed any less. She blames my lack of feeding on the dissapearence of the fish, so i am trying to figure out where they are going.

My endlers population has actally decreased from three to two. They also breed once, and i think the remaining two are the surviving offspring of the original three. I have no idea where my fish are going. IS it possible that they get too adventurous and are getting trapped in the java moss? My teacher had a pregnant molly that was in a separate tank with some java moss and became entangled. She saved it just in time. That possibility never occurred to me, and i was wondering if it could have been the cause of my disappearing fish, but i have so much of this stuff that it seems almost plausible to me. And to think i keep it all to save the shrimp/fish offspring...
what do you think? thanks in advance