Hi. I have a male guppy. He's been in my 10 gallon tank alone for about 2 weeks. Today I went out and picked up 2 more male guppies. The one I had in there seems to be nipping at the new guppies. Doesn't seem like it's overly aggressive, and the new ones aren't hiding, just swimming away a little. Is this normal behavior for guppies when new fish are introduced?