Manchineel

I got home from work today and one of my CPDs was dead, stuck between the glass and my intake sponge. I removed him and cut down my sponge to be flush against the glass, is there anything more I can do to prevent this from happening?

I don't really want to add shrimp into this tank, I was just worried about fish on fish violence. I don't really want to get a bunch of another small fish either, I thought about guppies but I don't know how I could control their numbers, seems like nothing would really eat their fry.

I am currently cycling this 30 gallon tank and I plan to put in CPD and Venezuelan corydora. I wanted to get something blue swimming around in there for a nice contrast and looking for some ideas. My first thought was a dwarf neon or powder blue (female) gourami since they have small mouths, but the CPDs are so small I am still worried about them. My plants also have a long way to go before they can really provide adequate cover. Second Idea was looking into if my fish store could order some blue mollies and throw 1 male with 4 female. Blue dream shrimp were briefly considered, but I would rather not crowd the bottom of my tank.