I used to have a valentini puffer that I would feed by hand, sometimes when holding a chunk of food above the waterline he would spit a stream of water at it, I swear he was trying to knock it out of my hand....

I think that the water is not fresh.I mean the water quality is not good.It may contain the algae inside.If you have a pH of water then it would be better for fish.

Your comment is confusing but if you mean a neutral pH then that's not correct for marine fish, it's supposed to be slightly alkaline.