Russian moss balls and algea eaters

[Annie/Aggie]

I purchased what my LFS called a "russian moss ball" about a week ago. ( the web sites I've found call it a japanese moss ball, looks the same to me.) I bought it because I think it looks awesome but my 2 algea eaters, who were very small, seem to have grown a great deal pretty fast. I've had the algea eaters for over 2 months and they had stayed to less than an inch long, now they are longer and noticeably fatter.
Are they eating my moss ball does anyone know? I haven't noticed them near it as yet. The algea eaters are just your most basic type with the brown body and black stripes.

 

[noncentric]

I'm assuming you're referring to 'marimo balls' (Cladophora aegagropila).

Even though it is an "algae", the algae eaters shouldn't bother the balls. Also, it sounds like you might have a Chinese Algae Eater - in which case, it will likely stop eating any kind of algae when it matures. As they age, CAE's preference for algae diminishes and they go more for regular foods.