sprouting seed in my aquarium

Question
About a month ago, my son dropped a sunflower seed from the bird dish
into the aquarium.  It blended in with the gravel so I never fished it out.  
About a week ago I noticed that the seed has sprouted and it was floating
around in the tank.  I left it there to see what would happen and it is still
growing.  My question is: Are sunflower seed plants harmful to the fish? Are
they aquatic plants? And do you think I should leave it there for oxygen, or
take it out?  By the way, I have 1 glofish and 3 neons.  They seem to be doing
fine and haven't been bother by the plant at all.  

Thanks in advance for your advice.

Answer
Hi Valerie,
Its fascinating how a terrestrial plant like Sunflowers will grow in submerged aquatic conditions as seedlings.

I think -maybe- if the sprouted seedling gets some air from floating around it may continue to grow but eventually it may succumb to a lack of certain nutrients or sunlight. You should take it out and give it a little container of soil and watch it grow! :-)

Sunflowers nor sunflower seeds aren't harmful to fish and are safe for most critters.

Hope this helps!
Karen~