I have friends who had a son with a similar obsession. He has a form of autism. They worked with him intensively and he's at the point where he no longer melts

I have friends who had a son with a similar obsession. He has a form of autism. They worked with him intensively and he's at the point where he no longer melts down. Everyone one is different and I'm not inferring anything about your child by mentioning this. Until reading this I'd forgotten about his obsessions years ago. If you met him now you'd have no idea what he was like before. I don't even know what they did only that it was hours per day for years and year. I was amazed at his transformation. On a more helpful note, what about a fish tank pump and a pond or other water holding tank?