pumpkinseed behavior

I have 4 sunfish in my 40 gallon 3 are green sunfish and 1 is a pumpkinseed(he's king of the tank). The pumpkinseed is the only fish I noticed that "forages" like this. He will pick up and spit out individual pieces of gravel. I have a few questions what is he searching for? What should I put in to encourage this behavior/make his efforts not fruitless.

I have 4 sunfish in my 40 gallon 3 are green sunfish and 1 is a pumpkinseed(he's king of the tank). The pumpkinseed is the only fish I noticed that "forages" like this. He will pick up and spit out individual pieces of gravel. I have a few questions what is he searching for? What should I put in to encourage this behavior/make his efforts not fruitless.

Pumpkinseed are noted foragers. The fish is probably looking for inverts. Perhaps confusing the gravel for snails? In much of their range pumpkinseeds are called shell crackers, they seem to enjoy eating snails.

Pumpkinseed are noted foragers. The fish is probably looking for inverts. Perhaps confusing the gravel for snails? In much of their range pumpkinseeds are called shell crackers, they seem to enjoy eating snails.

I have read that they have a special organ in their throats designed to crush snail shells.

I have read that they have a special organ in their throats designed to crush snail shells.

They have strong pharyengeal muscles in their throat (along with teeth etc.) that lead some to beleive that they are specialized snail eaters. Despite this mine still won't eat a hard cichlid pellet.

If I throw a few snails in there they won't gunk up my tank in life or after being eaten will they?