Last week, I bought 3 shrimp, a marimo ball, and 2 mollies (one male, one female) to go along with my 3 Glofish tetras (2 females, 1 male) in my 15 gallon tank. When I first got the tank, I made sure to add plenty of plants and a structure where the fish can go in and out of (but I can still see inside it completely). The shrimp are a bit bigger than my thumbnail (like 2 cm). When I first added the shrimp, I did exactly what the employee from Petco told me to do. I turned off the light and gave the other fish some food so they won't peck at the shrimp on their way down to the bottom. And it went great! The shrimp seemed right at home. But the next day, I spotted two of them, but not the last one. My dad said the fish probably ripped it apart and ate it. My mom said it probably hid inside the plants or burrowed under the rocks. What I did notice, though, was a molted shrimp shell. It looked like it belonged to the largest shrimp or the one that I couldn't find. I thought it's possible that the shrimp molted and felt vulnerable, so it hid very well. The next day, two were missing, and it appeared that it was the other two. And lo and behold, there was the other shrimp that I couldn't see the day before. Now it is day two since the other two disappeared, and I can't see either of them. This time, there aren't any shells lying around. Is it possible for those small shrimp to hide under the gravel or under decorations? Or did the fish really eat them?